William Meldrum (1839-1890) was my g-grandfather. He was from Greene Co., IL, but enlisted in the MO 1st Cav. He was a grandson of Rev. William Meldrum who I mentioned in previous posting.
Many libraries offer Heritage Quest free to their members. It has more than census info, there are history/genealogy books also.
In the census you can only search for head of household, but you can also enter place of birth, age group, county of residence, etc. to narrow it down. Sometimes I just search for first name, county & place of birth.