Lynbrook Station was originally opened as Pearsall's Corner Station on October 28, 1867 by the South Side Railroad of Long Island. The station's name was shortened to Pearsall's in April 1875, and would hold onto that name until 1893. In 1880, the station became the northern terminus of the New York and Long Beach Railroad, a railroad line that was acquired by the LIRR and became the Long Beach Branch in 1886. When the NY&LB was added, the station gained the "PT Tower", which controlled the junction with the Montauk Branch until 1910, when Long Beach Branch tracks were extended to Valley Stream Station. The station was rebuilt in 1881, electrified on September 8, 1910, and then remodeled sometime in 1920, only to be razed in 1938 as part of a grade elimination project that was occurring along the Montauk, Atlantic and Babylon Branches throughout the Mid-20th Century. The third and current elevated station was located, 1,113 feet west of its former location and was opened to the public on October 18, 1938.
This station has two 10-car-long high-level island platforms. The north platform, Platform A, is adjacent to Tracks 1 and 2 of what is physically considered the Montauk Branch but is generally used by Babylon Branch trains. The south platform, Platform B, is adjacent to Tracks 1 and 2 of the Long Beach Branch. The rail line has four tracks at this location, and the two branches split immediately east of the station.
The station is listed on timetables and maps, as being served by both Long Beach and Babylon Branch trains. Both Long Beach and Babylon Branch trains stop there hourly (every 30 minutes when combined) on an alternating basis during off-peak hours. Peak service is about every 20 minutes or less. Late night service is every two hours.