The Tenth Circuit hears appeals from U.S. district courts located in Oklahoma, Kansas, New Mexico, Colorado, Wyoming, and Utah. The Court's geographic jurisdiction covers those states, plus those portions of the Yellowstone National Park extending into Montana and Idaho.
The Court Web site includes contact information, published and unpublished opinions from 1995, order, forms, rules & jury instructions, bar admission information, etc. For questions, call the court clerk's office at (303) 844-3157.
The Court also posts a detailed Practitioner's Guide.
You can search opinions back to the 1920s for free using Google Scholar.