At some Guitar Center stores, employees are still allowing customers to try out models of guitars. Dillard’s, a department store chain popular in the South, is still welcoming shoppers looking for clothing and makeup. And Michaels, the arts and crafts chain, says it is keeping many of its stores open to provide supplies to parents teaching their homebound children. “We are here for the makers,” the retailer said in an email to one concerned customer.

In states hit hard by the coronavirus, like New York and California, governors and mayors have mandated the closure of all but the obviously essential stores, like supermarkets and pharmacies. And the Department of Homeland Security has laid out guidelines for businesses across the country to follow when deciding whether to stay open, even in regions not known to be hot spots for the virus. The agency is careful to note that its definition of a “critical” work force is not an official standard, leaving it up to corporations to decide for themselves.

Given this latitude, retailers have kept thousands of stores open, even as health experts warn that the virus is likely to spread more widely across the country in the coming weeks. Several retailers — like Sears, Kmart, and Joann Fabric and Craft Stores — have provided employees with letters they can share, arguing that their businesses are essential.

That some retail stores are staying open while other businesses have closed reflects the piecemeal approach to combating the pandemic in the United States. There are emergency orders limiting business to essential retailers in about half the country, but much of the South and West has no such government restrictions.