Anaheim chillis are the most popular chilli in the United States. They are named after the southern california state where they were first cultivated commercially. They are originally from New Mexico and there they are called Hatch chillis. The Hatch chilli, due to the different growing conditions are quite a bit hotter.A
Anaheim are mostly picked at the green stage, and while some hybrids rippen red, they normally stay a greenish brown when ripe. The dried green chillis, as popular with most Mexican chillis are renamed and are called Seco del Norte.
These thicker walled chillis are great for roasting, stuffing, pickling and eating fresh, and being from about a 5th of the heat of a Jalapeño to at max the heat of a mild Jalapeño, they don't blow the taste buds of unsuspecting diners. They can replace capsicum (Bell peppers) to spice things up a bit, or Jalapeño to tone it down a bit.
In Cajun cuisine these peppers are pat of the mire poix.
These peppers dry, can and freeze well for later use.
The photo is of my Anaheim plant with great fruit set.