Home sales at River Islands at Lathrop and elsewhere will help start moving a proposed satellite county center toward becoming a reality in Manteca. San Joaquin County agreed several years ago to locate a satellite county center in Manteca to serve Tracy, Manteca, Lathrop, Ripon, and Escalon. The city spent $3.8 million for 10 acres on Daniels Street where it intersects with Fishback Road.