Leominster ( LEM-ən-stər) is a city in Worcester County, Massachusetts, United States. It is the second-largest city in Worcester County, with a population of 40,759 at the 2010 census. Leominster is located north of Worcester and northwest of Boston. Both Route 2 and Route 12 pass through Leominster. Interstate 190, Route 13, and Route 117 all have starting/ending points in Leominster. Leominster is bounded by Fitchburg and Lunenburg to the north, Lancaster to the east, Sterling and Princeton to the south, and Westminster to the west.