The first true Walmart opened on July 2, 1962, in Rogers, Arkansas. Called the Wal-Mart Discount City store, it was located at 719 West Walnut Street. He launched a determined effort to market American-made products. Included in the effort was a willingness to find American manufacturers who could supply merchandise for the entire Walmart chain at a price low enough to meet the foreign competition.
As the Meijer store chain grew, it caught the attention of Walton. He acknowledges that his one-stop-shopping center format was based on Meijer’s innovative concept. Contrary to the prevailing practice of American discount store chains, Walton located stores in smaller towns, not larger cities. To make his model work, he emphasized logistics, particularly locating stores within a day's drive proximity to Walmart's regional warehouses, and distributed through its own trucking service. Buying in volume and efficient delivery permitted sale of discounted name brand merchandise. Thus, sustained growth— from 1977's 190 stores to 1985's 800— was achieved.
According to wikipedia