The park is situated on the eastern shore of the Hell Gate, a strait of the East River, between Ditmars Boulevard to the north and Hoyt Avenue to the south.

The Robert F. Kennedy (Triborough) and Hell Gate Bridges respectively pass over the park's southern and northern sections.

The pool and bathhouse were designed by John Hatton during a Works Progress Administration project in 1935–1936 and was used for the United States Olympic Trials for swimming during 1936, 1952, and 1964.

The Hell Gate Bridge, carrying Amtrak's Northeast Corridor and the New York Connecting Railroad, crosses over the northern section.

[10][11] There is also a plaque commemorating the PS General Slocum,[12] which caught fire and sunk in the Hell Gate in 1904,[7][13][14] killing over a thousand people.

The deck is surrounded by concrete bleachers and enclosed by a brick perimeter wall topped by a wrought iron fence.

[4][45] As designed, the pool entrance was flanked by two stainless steel sculptures created by Emil Siebern, which depicted female athletes.

Above the center bays on each side are Art Deco-style aluminum letters indicating the respective genders' locker rooms.

Except for the central bay on each side, there are openings with glass blocks topped by metal louvers; these are separated by fluted brick piers.

At the northern and southern ends of the west facade, there are semicircular coves with doorways that lead to the bathhouse's locker rooms.

The eastern wings of the bathhouse, to the north and south of the entrance court, each contain two bays of horizontal glass-brick bands.

[62][63] In 1907, the New York Connecting Railroad (NYCN) bought 13,566 square feet (1,260.3 m2) from the East River Land Company for a right-of-way to build the Hell Gate Bridge through Astoria Park's site.

[59] Also in 1907, the city government was slated to pay the East River Land Company $200,000 for nine hundred lots totaling 70 acres (28 ha).

However, the city balked on acquiring the land, contending that the selling price was too high and citing the company's decision to grant the NYCN an easement.

[59][67][68] That July, the New York City Board of Estimate authorized a park to be laid out on the plot between the East River, Ditmars Boulevard, 19th Street,[b] and Hoyt Avenue.

[71] The city acquired 56.25 acres (22.76 ha) in October 1913,[59][72] and shortly afterward, the Board of Estimate renamed the park for mayor William Jay Gaynor.

[83][84] Construction of a seawall and an approximately 3,000-foot-long (910 m) section of Shore Boulevard started in April 1926,[74][85][86] and a memorial to victims of World War I was dedicated that November.

The facilities included a playground, skating rink, athletic field, restroom, six tennis courts, and two baseball diamonds.

[74] In 1934, mayor Fiorello H. La Guardia nominated Robert Moses to become commissioner of a unified New York City Department of Parks and Recreation.

At the time, the United States was experiencing the Great Depression; immediately after La Guardia won the 1933 election, Moses began to write "a plan for putting 80,000 men to work on 1,700 relief projects".

[98][99] The pools would be built using funds from the Works Progress Administration (WPA), a federal agency created as part of the New Deal to combat the Depression's negative effects.

Moses, along with architects Aymar Embury II and Gilmore David Clarke, created a common design for these proposed aquatic centers.

Each location was to have distinct pools for diving, swimming, and wading; bleachers and viewing areas; and bathhouses with locker rooms that could be used as gymnasiums.

The pools were to have several common features, such as a minimum 55-yard (50 m) length, underwater lighting, heating, filtration, and low-cost construction materials.

To fit the requirement for cheap materials, each building would be built using elements of the Streamline Moderne and Classical architectural styles.

[114] Siebern's athletic sculptures at the bathhouse had been removed by 1943,[46] when Moses wrote that they "have long since traveled [...] from the storage yard to the scrap heap".

[46] This was part of a $5 million renovation that also included a repaved parking lot, as well as improvements to the baseball and soccer fields, running tracks, tennis courts, paths, and lighting.

[130][131] The landmark designation covered the pool and bathhouse, as well as part of the surrounding park between the Triborough and Hell Gate Bridges.

[145] After the design process was completed, community members advocated for the diving pool's restoration,[38][36] though NYC Parks refused to change the plans.

[151][152] The second phase, which includes rebuilding the wading pool and Charybdis Playground for $12.5 million, was completed in September 2021,[153][154] following a temporary opening and re-closure that July.