The USA stamp identifies the piece as American made, although it could have been produced by any one of many American pottery companies. The most prolific users of the USA mark were Shawnee and McCoy. Identify the true unfinished color of the piece by examining any unglazed areas on the bottom.

How can I identify a piece of pottery?

Look at the bottom of your piece of pottery for a design that may indicate the pieces origin, even without the potters name or the factory name. Indentations in the bottom of the piece, allowing it to sit flat, may also be indicative of its origin.