The pioneers who shaped Palm Beach County left a generous architectural legacy.

The free-spending and opulent designs of the Florida Boom — when visionaries flocked here to create a paradise in the sun — is evident in all but three of 18 sites listed on the National Register of Historic Places.

Only the prehistoric Indian mounds near Canal Point, the Jupiter Lighthouse and the West Palm Beach home of black pioneer Alice Mickens reflect different periods.

A listing on the national register, in addition to denoting historical and architectural significance, can qualify a site for other benefits, according to John Johnson, director of the Historic Palm Beach County Preservation Board.

The property will be considered for federally funded projects, become eligible for federal tax benefits and qualify for historic preservation grants when funds are available.

But the status does not prevent owners from changing or even demolishing a site, unless it receives federal money. Local ordinances often do carry such restrictions.

“In some ways a national listing is academic,” said Johnson, “whereas a local ordinance really protects the property in a legal way.”

Here is a city-by-city guide to the county’s 18 national historic sites, as well as three that have been demolished. The numbers correspond with a locator map on this page.

BOCA RATON

(1) Boca Raton Old City Hall, 71 N. Federal Highway: One of the numerous architectual gems by fabled pioneer Addison Mizner, the 1927 building houses three historical agencies.

The gold-domed structure is home to the Boca Raton Historical Society, the Historic Boca Raton Preservation Board and the Historic Palm Beach County Preservation Board.

Since its construction, the building has been home to city offices, police and fire departments, a fire chief’s residence and a Women’s Club library.

Like most of Mizner’s works, the edifice follows a Mediterranean Revival style. Restoration work on the building, named a national historic site in 1980, began in June 1983 and was completed in November 1984.

(2) Florida East Coast Railway Passenger Station, South Dixie Highway: The train depot, originally built as a stopping point for the monied patrons of the Boca Raton Hotel and Club, has not served the FEC Railway in about 20 years.

But restoration could begin as early as January 1987.

Precisely who designed the Mediterranean-style structure is a point of dispute, according to historical records.

While it clearly follows the style of Mizner, the 1929 edifice was erected well after the flamboyant architect’s financial empire crumbled following his creation of the Boca Raton Hotel and Club.

Some historians contend it was created from Mizner’s blueprints.

(3) Mizner Administration Buildings, Dixie Highway and Camino Real: Much of the actual work that carried out the genius of Mizner was done within these two Spanish-style buildings.

The north building housed the Mizner Development Corp. and Mizner’s real estate sales offices. The south edifice contained the drafting rooms of Mizner’s engineer, Carl Riddle.

Mizner, a Californian who had studied Spanish art and culture, brought his visions to Boca Raton in 1924 after impressing Palm Beach with his designs. He bought up 17,500 acres of land, employed hundreds of people and started plowing through the mangrove swamps.

“It was from the construction of the Administration Buildings that they planned the city,” said Johnson, director of the Preservation Board.

The buildings were used by the Boca Raton Hotel and Club — the Mizner creation built two years earlier — as employee dormitories from 1928 through 1983.

The buildings, completed in 1928, were designated as a national historic place last July. Private developers who purchased the property are renovating the site for a restaurant and offices.

BOYNTON BEACH

(4) Boynton Beach Woman’s Club, 101 S. Federal Highway: The club, once the social hub of the city, reflects an era of gala balls and tea parties.

The city’s only building to be designed by architect Mizner, the Spanish- style clubhouse was completed in 1926. It served as headquarters for the club, founded 16 years earlier, and as the first community library.

Land and materials were furnished by Nathan Boynton, for whom the city was named.

Club president Marie Shepard, a city native, reveres the building’s history.

“I find it (phenomenal) that the ladies were able to hang on to it through two hurricanes, the Depression, and the widening of Federal Highway,” she said. But time and weather have taken a toll on the building, named a national historic site in 1979. Fund-raisers have been working for the past three years to raise $500,000 for a face lift.

CORBETT (J.W.) WILDLIFE MANAGEMENT AREA

(5) Big Mound City, 10 miles east of Canal Point: Please see story, page 1B.

JUPITER

(6) Jupiter Inlet Lighthouse, Loxahatchee River and Jupiter Sound: As the county’s oldest building, the lighthouse has beamed down on nearly 127 years of history.

Getting the project started took an act of Congress. The federal government appropriated $35,000 after President Franklin Pierce set aside 61 acres of land to build a lighthouse for guiding boats into the Jupiter Inlet.

Works crews were delayed by swarming mosquitoes, prowling alligators and angry Seminoles.

The 105-foot tower was finally completed in 1859. But its operation stopped from 1861 to 1866 to discourge blockade runners during the Civil War.

In more modern times, the lighthouse was dimmed for part of World War II. The Coast Guard’s responsibility since 1939, it was designated a national historic site in 1973.

LAKE PARK

(7) Kelsey City City Hall, 535 Park Ave.: The 1927 building signifies an era when Lake Park was called Kelsey City and popularly known as “The Miracle City of Florida.”

It was thus dubbed by Harry S. Kelsey, a Bostonian who arrived in 1920 and spent the next eight years creating what he also referred to as “The Gateway to the World’s Winter Playground.”

Consulting with a Harvard professor, Kelsey went about building what may have been the area’s first planned unit development. It was designed to recognize long-range growth and offer a variety of services, from schools to transportation.

The historic site, now Lake Park Town Hall, is the last remaining structure from this period. It was listed on the national register in 1981.

LAKE WORTH

(8) Gulfstream Hotel, 1 Lake Ave.: The picturesque Gulfstream Hotel, overlooking the Intracoastal Waterway, has operated every winter since since it opened in 1925, except for seven years after the 1929 stock market crash.

Battered by storms, a victim of changing times and loss of business, the Gulfstream has survived.

Now restored to much of its former opulence, the Gulfstream will remain open this summer, marking the first time it has operated year-round.

The renovation begun two years ago has revitalized the flamingo pink exterior and interior walls, highlighted by Atlantic blue. Potted palms and rattan plants add to the Florida Boom effect.

The owners’ plans for additional parking behind the hotel and at the now- demolished Gulfstream Inn across Lake Avenue, as well as redevelopment of a small restaurant building outside the hotel, is scheduled for review by the City Commission Monday.

PALM BEACH

(9) The Breakers Hotel Complex, South County Road: If any one place symbolizes Henry Flagler’s legacy of grand style, it is The Breakers.

Flagler, railroad magnate and co-founder of Standard Oil with John D. Rockefeller, is credited with establishing the island of Palm Beach as a winter mecca for the wealthy.

After a fire destroyed the Palm Beach Inn in 1903, Flagler built the original Breakers, surrounding it with cottages for some of the country’s most prominent families. The hotel became the core of the social season.

In 1925, 12 years after Flagler’s death, The Breakers was destroyed by fire. It was replaced a year later by the five-star hotel of today. The palatial spread required $6 million, 1,200 craftman and 91 artisans imported from Europe to create.

Designed by Leonard Schultz, the architect who created the Waldorf-Astoria, the 567-room hotel was inspired by Italian Renaissance artistry.

“(It) is possibly the most prestigious of all American resort hotels,” Roger H. Grunke, a state historic sites specialist, wrote in nominating the hotel to the national register in 1971.

(10) Henry Morrison Flagler House (Whitehall), 1 Whitehall Way: Railroad baron Flagler built Whitehall for his third wife, Mary Lily Kenan, in 1901. Today, restored as a museum, the Spanish revival mansion reveals the lavish lifestyle of Palm Beach’s premier pioneer.

Designed by John M. Carrere and Thomas Hastings, Whitehall’s significance reflects Flagler’s import. Starting in the 1880s, he is credited with singlehandedly developing Florida’s east coast, building a railroad from Jacksonville to Key West, and establishing St. Augustine, Daytona, Miami and Palm Beach as famous resorts.

In 1925, Flagler added a 300-room hotel to Whitehall, which has since been turned over for lectures, exhibits, charity balls and the Palm Beach County Historical Society.

Whitehall, now operated by descendants of Flagler, opened as a museum in 1960. Many original furnishings have been returned and rooms faithfully restored.

(11) Mar-A-Lago National Historic Landmark, 1100 S. Ocean Blvd.: Mar-A-Lago, the 118-room monument to Roaring ’20s ostentation, could be called the crown jewel among county historical sites.

Through a congressional act in 1980, the pink-and-brown mansion became the area’s only structure declared a National Landmark, which conveys an even more selective distinction than does the National Register of Historic Places.

Only sites with prominent national significance can become landmarks, while historic places usually reflect local or state importance, said Johnson of the Preservation Board.

The house was built in 1927 for Marjorie Merriweather Post, cereal heiress and original grand dame of Palm Beach old guard society. With lavish style, she entertained presidents, ambassadors, movie stars and industrial giants.

Ziegfeld Theater creator Joseph Urban designed the sprawling edifice, which lies on 17 acres and means “Sea to Lake” in Spanish. Flamboyant New York developer Donald Trump bought the estate last year for $5 million.

(12) Palm Beach Daily News Building (former), 204 Brazilian Ave.: The old newspaper offices pay tribute not only to Mizner’s style but to a daily kind of journalism that has continued capturing the wealthy island’s spirit.

Henry Flagler owned the Palm Beach Daily News before it moved into the historic site, where Palm Beach Life magazine, the Palm Beach Weekly and the Palm Beach Journal were all printed at one time.

Built by Mizner in 1926, the Spanish-style building used many of the architect’s favorite materials, such as roof and floor tiles, elaborate grill work and stained glass windows, according to area historian Donald Curl.

Now owned by a partnership, the building is being converted into offices under a $200,000 renovation plan.

(13) Paramount Theater Building, 145 N. County Road: The fabled Paramount opened Jan. 9, 1929, with the premier showing of Beau Geste.

“There is no other building in Florida with the special dramatic flair as this one,” according to a 1979 description contained in the Florida Master Site File.

Designated as a national historic site in 1973, the edifice retains nearly all of its original form and appearance with minor exceptions.

The theater stopped operating in 1969.

Over the years, a series of developers tried with varying success to turn the Paramount into a chic shop and office center. A $6.5 million renovation was finished last year, and new ownership by an Ohio bank appears to have boosted the venture.

(14) U.S. Post Office, 95 N. County Road: The Palm Beach post office was first listed Jan. 16, 1887, as Palm City. The name was changed after Edmund M. Brelsford, the first postmaster, learned there was already another Palm City in Florida.

Mizner originally designed a $200,000 post office, but the federal government rejected it as too costly.

Years later, although the government chose a standard-issue post office, architect Louis A. Simon still chose a Spanish style, with a two-tier Spanish barrel tile roof, marble stairs and brass handrails.

Constructed in 1936-37, the building was designated as a national historic place in 1983. It is one of two post offices on the island.

(15) William Grey Warden Residence, 112 Seminole Ave.: Known as the Warden House, the home was named for the son of a founder of Standard Oil and the chairman of Pittsburgh Coal.

Built by Mizner in 1922, the 32-room edifice typifies Mizner’s synthesis of Spanish and Italian Rennaissance styles.

In 1977, the Warden House was threatened with demolition and slated to be replaced with townhouses. After two years of litigation, the building was saved when Robert Eigelberger, a local businessman and preservationist, got approval to convert the home into a six-unit condominium.

The structure, which occupies the entire oceanfront block between Root Trail and Seminole Avenue, was designated a national historic place in 1984.

WEST PALM BEACH

(16) Hibiscus Garden Apartments, 619 Hibiscus St.: Built in 1926, the Hibiscus Garden Apartments have remained virtually unchanged over the past six decades.

Built to relieve a housing shortage and provide accommodations for Florida land investors, the structure originally was designed for seven stories.

But faulty railroad lines caused a major shortage of supplies. This probably led to the three-story design, according to West Palm Beach architect John H. Stevens.

Stevens’ firm has created a $1 million renovation plan, which calls for preserving the Spanish character of the 57-unit national historic site. But thus far developers have been unable to secure financing.

(17) Alice Mickens Residence, 801 Fourth St.: Alice Mickens, a black city pioneer, never had her own children. But seven or eight youngsters found their way to the house and were fed and raised there.

And prominent blacks from out of town, not allowed to stay at hotels, lodged at the house where Mickens has lived since 1917. It became a gathering place for visitors seeking intellectual, political and social exchange.

The house, with its broad roof, double front window and carved ceilings, was built by Mickens’ late husband, Haley.

The house was designated as a national historic site last summer.

(18) Seaboard Coast Line Passenger Railroad Station: The Seaboard Line laid tracks to the Palm Beach area as late as 1921-24, some 30 years after Flagler built his FEC Railway Line.

Seaboard Line President S. Davis Warfield built a cross-state line to serve West Palm Beach, Miami and Homestead in 1926, making a direct rail connecion from one coast to the other across the state.

The station, named a national historic site in 1973, “combined their taste in architecture, and their desire for service and convenience for the community related to their vacation and retirement,” a historic American building survey noted.

DEMOLISHED

Palm Beach Winter Club, U.S. 1, North Palm Beach: Built as a country club at the height of the Florida Boom in 1926 for sewing machine heir Paris Singer, the building later became the hub of activity in the north county.

Once owned by magnate John D. MacArthur, the structure was taken over by the village in 1961. But as the fortunes of the surrounding area grew, the fortunes of the Winter Club fell.

Lack of care led the building to deteriorate to the point where it was condemned in 1977. A local battle began over whether to preserve the structure.

A Circuit Court judge ruled it should be decided by a referendum, and in March 1984, with 3,200 ballots cast, the decision to raze the building carried by a 167-vote margin. The building was razed six months later.

Bingham-Blossom House, 1250 S. Ocean Blvd., Palm Beach: Erected in 1893, the home was the first privately-owned residence built on the ocean in Palm Beach.

The shingle-style home was known as “Figulus,” which refers to a potter’s craft — probably a pun on the name of the original owner, Dr. R. B. Potter.

It was razed some time ago.

Brelsford House, 1 Lake Trail, Palm Beach: Edmund M. Brelsford, one of the area’s earliest settlers, Palm Beach’s first postmaster and a pioneer in South Florida banking, arrived on the shores of Lake Worth in 1881.

He lived in Palm Beach for 60 years in a shingle-style house that was named a national historic site in 1974. The Royal Poinciana Chapel later assumed the property, but church trustees were unable to restore the run-down home and it was razed a few years later.

Upon Brelsford’s death in 1937, a local newspaper paid him a tribute that seems fitting for any of the first settlers who left their mark:

“His career illustrates the best traits and characteristics of American manhood and traditions,” the obituary read, “and his life record is a romantic epic of adventure, pioneering, successful and almost magical realization of ambition and dreams.”