U.S. cities that blazed the marijuana legalization trail now have a high concentration of 420-friendly vacation rentals, a new study by Upgraded Points shows.

Why it matters: Cannabis-cations are one piece of the growing multi-billion dollar weed economy.

The big picture: Unsurprisingly, three Colorado cities — Boulder, Denver and Colorado Springs — are among those with the highest concentration of pot-friendly rentals per the study.

• Burlington, Vermont; Las Vegas; Scottsdale, Arizona; and Portland, Maine, also top the ranking.
• Chicago; Reno, Nevada; Minneapolis; Columbus, Ohio; and New York have the smallest share of smoke-friendly rentals among states where weed is legal.
• The list includes cities where recreational marijuana use is legal, but sales are not.

The intrigue: Columbus, where weed-friendly stays average $127 per night, is the cheapest place for toke travels, according to the study.

• A one-night stay in San Diego, Scottsdale or Phoenix — the priciest pot-friendly rental spots — costs around $300-$360+.

Go deeper: Organizers plan inaugural "shroom" festival in Denver