Rensselaer County Then and Now: Celebrating 225 years of Rensselaer County History Map of Rensselaer County from 1829 Gallery view of the Then and Now images and artifacts from our collection. The historical society, at 57 Second St., is open from noon to 5 p.m. Thursday to Saturday. Rensselaer County is celebrating it’s 225 anniversary. Come and see our new Then and Now exhibit. Petersburgh basket and rent receipt.