Roslyn Heights saw a major economic boom in the 1860s, shortly after the Long Island Rail Road's Oyster Bay Branch was built through and opened in the area.

[4][5] It moved to its present location at 66 Mineola Avenue in 1967, with the dedication ceremony taking place on Sunday, July 30, 1967.

[6][7][8] These proposals were ultimately unsuccessful, and all of Roslyn Heights remains an unincorporated hamlet within and directly governed by the Town of North Hempstead to this day.

[3][11] The Roslyn Plaza Urban Renewal Project began in the early 1970s and the final phase broke ground in 1983.

[4] According to the United States Census Bureau, the CDP has a total area of 1.5 square miles (3.9 km2), all of it land.

According to the United States Environmental Protection Agency and the United States Geological Survey, the highest point in Roslyn Heights is located at its northern border with Roslyn on Hillside Avenue, at approximately 210 feet (64 m), and the lowest point is located near its southeastern border, near the Wheatley Hills Golf Club, at approximately 100–110 feet (30–34 m).

Parks and recreation facilities within Roslyn Heights include:[9]As Roslyn Heights is an unincorporated part of the Town of North Hempstead, it is directly governed by the town's government in Manhasset.

[9][32] Roslyn Heights is located entirely within New York's 3rd Congressional district, which as of March 2024 is represented in the United States Congress by Thomas R. Suozzi (D–Glen Cove).

[9][33] Like the rest of New York, Roslyn Heights is represented in the United States Senate by Charles Schumer (D) and Kirsten Gillibrand (D).

[34] In the 2024 U.S. presidential election, the majority of Roslyn Heights voters voted for Donald J. Trump (R).

[9] Roslyn Heights is served by the Oyster Bay Branch of the Long Island Rail Road.

[40][41] PSEG Long Island provides power to all homes and businesses within Roslyn Heights.

[9][43] The southern part of Roslyn Heights is within the Nassau County Sewage District.

[9][44] The portion of Roslyn Heights north of the Northern State Parkway is located within the boundaries of (and is thus served by) the Roslyn Water District, the area of Roslyn Heights between the Northern State Parkway and the Wheatley Hills Golf Club is located within the boundaries of (and is thus served by) the Albertson Water District, and the portion of the Wheatley Hills Golf Club within Roslyn Heights is located within the boundaries of (and is thus served by) the Village of East Williston's water system.