Rimer is an unincorporated community in Madison Township, Armstrong County, Pennsylvania, United States. It has also been called Rimerton and Rimerton Station. A post office called Rimer was established in 1868, with John Rimer as postmaster. It remained in operation until 1951. Rimerton Station and Rimer P.O. appear in the 1876 Atlas of Armstrong Count…Rimer is an unincorporated community in Madison Township, Armstrong County, Pennsylvania, United States. It has also been called Rimerton and Rimerton Station. A post office called Rimer was established in 1868, with John Rimer as postmaster. It remained in operation until 1951. Rimerton Station and Rimer P.O. appear in the 1876 Atlas of Armstrong County, Pennsylvania. Frank Mast, who kept a store, was postmaster in 1913.