Overnight parking in Walmart parking lots is popular among RVers. Walmart’s official policy is to allow RVers to park overnight where they are able. Permission is granted by individual store managers, based on availability of space and local laws. But there are more than 900 Walmart stores nationwide where overnight RV parking is prohibited. That’s about 23 percent of all Walmart stores in the United States. A free Walmart RV Parking Directory is available for download. The PDF file lists stores where overnight RV parking is not allowed.