Colorado Municipal Data Map (useful for viewing municipal boundaries)
Colorado Private Letter Rulings & General Information Letters
IRS Tax Exempt Organization Search
Code of Colorado Regulations
1 CCR 201-5: Sales and Use Tax - Special Rules for Specific Businesses
Municipal Codes
Colorado Department of Revenue - Revenue Online
Colorado Sales and Use Tax System (SUTS)
Municipal Online Portals
Colorado Department of Revenue - Taxation Division
Municipal Websites