At the Small Business Administration web site, you can check out the handy License and Permit page, which allows you to fill in your location and business type (or put in General Licensing), after which you’ll receive another page, full of more links. You can also click on your state directly.
Small Business Guidance – Road Map for Opening a Business in WA State
Road Map for opening a business (wa.gov)
State of Washington Business Licensing Service
Business Licensing Service and local licensing | Washington Department of Revenue
www.bls.dor.wa.gov
Washington State Department of Licensing Master License Service
WA State Licensing (DOL) Official Site: Business and professional licenses
