Let me know of any (non-commercial) links that should be added to this list.

Llewellyn Gulch

• Adventure Hikes and Canyoneering - more canyon trip reports
  
• American Canyoneering Association - official site
  
• Bogley - Utah outdoors forum, including canyoneering
  
• Jack Sanders-Reed - several slot canyons described
  
• Canyon Name Database and Canyon Tales - reference for the origin of canyon names, and a collection of general canyoneering stories, from Stefan Folias
  
• Joe's Guide to Zion National Park - Zion hiking guide; many canyons described
  
• Paria River/Buckskin Gulch - permit information from the BLM
  
• New Mexico Slot Canyons - nearly 100 narrow gorges in New Mexico
  
• Road Trip Ryan - canyoneering & climbing trip reports, links and photographs - focusing on more remote places
  
• Summitpost - trip reports and general information about Colorado Plateau slot canyons
  
• Todd's Hiking Guide - numerous hikes, many along slot canyons and the majority in Arizona, from Todd Martin
  
• Tom's Utah Canyoneering Guide - many canyons in Utah, technical and non-technical, with detailed maps and photographs
• Zion National Park - canyoneering in Zion, including detailed information on the park and nearby areas
  

Anyone interested in exploring slot canyons should consider purchasing some of the detailed guide books written by Michael Kelsey, in particular Non Technical Canyon Hiking Guide to the Colorado Plateau (seventh edition, 2018, with full color photographs); this has descriptions of over 150 hikes of which around 60 are along slot canyons. Another useful book is Hiking the Southwest's Canyon Country by Sandra Hinchman (third edition, 2004). More hikes are described in Canyoneering Arizona by Tyler Williams (revised edition, 2005).

For fuller descriptions of these and others, see the canyoneering books page.