Happy Mother’s Day Grimes County. Navasota Public Library Farmer’s Market, 1411 E. Washington Avenue in Navasota is Saturday, May 11 at 9 a.m. Senior Citizen Day at the Grimes County Fair is Friday, June 7 from 10 a.m. to 1 p.m. at the Grimes County Fairgrounds, 5220 FM Rd 3455 in Navasota.