Lincroft is an unincorporated community and census-designated place within Middletown Township, in Monmouth County, in the U.S. state of New Jersey. As of the 2020 United States census, the CDP had a population of 7,060, reflecting a 15.1% increase from the 6,135 residents enumerated at the 2010 U.S. Census, in turn a decline of 120 reside…Lincroft is an unincorporated community and census-designated place within Middletown Township, in Monmouth County, in the U.S. state of New Jersey. As of the 2020 United States census, the CDP had a population of 7,060, reflecting a 15.1% increase from the 6,135 residents enumerated at the 2010 U.S. Census, in turn a decline of 120 residents from the 6,255 counted in the 2000 U.S. Census.