There are many online sites that have the U.S. Census, searchable by name. FamilySearch.org is one of them, registration required but it's free. You don't indicate the years you are looking at. The U.S. Census started in 1790 and was taken every 10 years since. The latest to become public was the 1950 one. There is a 72 year privacy period, so the 1960 census won't become public until 2032. If you want some information since 1950, see my answer at: How can i obtain access to 1960 census in wayne county, Michigan for information on myself ? Be aware there is a fee for getting such census information for **each** family member you want to see, providing of course if you qualify to even ask for the information. As to state censuses. Most stopped doing them and relied on the U.S. Census. For example, the last NY state census was 1925. Ann Lainhart has a book on "State Census Records" 1992 that goes through the state censuses. Also another overview of what states did what census years prepared by Henry Durester can be found online at: babel.hathitrust.org/.../pt
