This research tests a form of the efficient markets hypothesis in the market for natural gas futures. Unlike other studies of futures markets, the test for market efficiency is conducted at numerous locations which comprise the natural gas spot market in addition to the delivery location specified in the futures contract. Natural gas spot and futures prices are found to be nonstationary and accordingly are modeled using recently developed maximum likelihood cointegration techniques. The futures market price is found to be cointegrated with nearly all of the spot market prices across the national network of gas pipelines. The hypothesis of market efficiency can be rejected in 3 of the 13 spot markets examined.