LaPlace is a census-designated place in St. John the Baptist Parish, Louisiana, United States, situated along the east bank of the Mississippi River, in the New Orleans metropolitan area. In 2020, it had a population of 28,841. LaPlace is the southern terminus of Interstate 55, where it joins with Interstate 10, and of US 51, where it terminates at the junction with US 61. LaPlace is located 25 miles west of New Orleans.