Colby cheese was developed in Colby, Wisconsin, in 1885, by Joseph F. Steinwand . Colby is similar to cheddar, but because it is produced through a washed-curd process, it is a softer, moister, and milder cheese. The washed-curd process means that during the cooking time, the whey is replaced by water; this reduces the curd's acidity, resulting in Colby's characteristically mild, pleasant flavor. It takes a little more than a gallon of milk to produce just 1 pound (454g) of cheese.

Longhorn is the best known of the Colby cheeses, all of which are typically sold in half-rounds. Colby should not be aged. It is best used shortly after purchase; otherwise, it soon dries out. Colby is widely available in health food stores, specialty stores, and markets.

Because it is such a mild cheese, Colby is seldom used in cooking. It is used as a table cheese, for grating and grilling, and in snacks and salads. Like Cheddar, it complements pears, apples, and apple cider nicely. When making sandwiches, enjoy Colby on rye bread.

Colby is sometimes mixed with Monterey Jack to produce a marbled cheese often called Colby-Jack or Co-Jack.