PEA RIDGE, Ark. (AP) — Walmart and Amazon are racing to speed up online order deliveries in rural areas of the U.S., a rich source of untapped sales that major retailers long wrote off as too sparsely inhabited, too remote or too impoverished to serve profitably. Walmart has a running start in the contest to build a loyal customer base in rural America. Roughly 90% of U.S. residents live within 10 miles of a Walmart store, and 45% of the company’s full-service Supercenters are in places with populations under 20,000, according to a report by investment bank Morgan Stanley. Competition for the underserved market, which the bank’s analysts estimated could be worth up to $1 trillion in annual sales, has intensified as remote workers swell the populations of small towns and communities on the far fringes of metropolitan areas. The same technology that makes it possible for more people to do office work from wherever they want is making it easier for the nation’s two biggest retail companies to get merchandise to them more efficiently.

Amazon last year invested $4 billion to bring same-day or next-day deliveries to 4,000 smaller cities, towns and rural communities. They included places like the coastal town of Lewes, Delaware, Milton, Florida, a city hat is considered the state’s canoe capital, Padre Island, Texas, which is about 37 miles from Corpus Christi, and Abbeville, Louisiana, known for its Cajun food scene.