Sea Girt is a borough in Monmouth County, New Jersey, United States. As of the 2010 United States Census, the borough's population was 1,828, reflecting a decline of 320 from the 2,148 counted in the 2000 Census, which had in turn increased by 49 from the 2,099 counted in the 1990 Census.Sea Girt was formed as a borough by an act of the New Jersey Legislature on March 29, 1917, from portions of Wall Township, based on the results of a referendum held on May 1, 1917. The borough was named for the estate of Comm. Robert F. Stockton, who had purchased a property in the area in 1853.In the Forbes magazine 2012 rankings of "America's Most Expensive ZIP Codes", the borough was ranked 197th, with a median price of $1,135,184.