Little House on the Prairie was on television from 1974 through 1983. However, it does get a bit more complicated than that.
The original series, Little House on the Prairie, aired from 1974 through 1982.
Little House: A New Beginning, aired from 1982 through 1983, which focused more on Laura and Almanzo, after the rest of the Ingalls family moved away.
Then in 1983, three more 2 hour movies were released – A Look Back to Yesterday, The Last Farewell (infamous for the town of Walnut Grove being blown up) and Bless All the Dear Children.