A new state analysis finds marijuana sales are strongest along Oregon’s border with Idaho – a state where recreational marijuana is not legal.

"In things you cannot make up, Oregon sales per adult along the Idaho border are 420% the statewide average,” wrote Josh Lehner of the Oregon Office of Economic Analysis in a report issued Friday. (420, of course, is a colloquial term referencing marijuana or cannabis consumption.)

Lehner found a similar phenomenon on Idaho’s border with Washington, another state where recreational marijuana is legal.

“The sales in counties along the Idaho border were much stronger than I anticipated,” Lehner wrote. “Obviously recreational marijuana is not legal in Idaho, but even after throwing the data into a rough border tax model that accounts for incomes, number of retailers, tax rates and the like, there remains a huge border effect.”

A “border effect” describes the phenomenon when two neighboring jurisdictions have different rules, prompting residents of one area to travel to the nearby region to take advantage of the different rules. Another well-known example is Southwest Washington residents traveling to Oregon to purchase products without paying a sales tax.

The Marijuana Policy Project says Idaho is the only state in the U.S. that with no law for medical or therapeutic marijuana. Supporters are gathering signatures to legalize medical marijuana there.

Beyond the border effect with Idaho, Lehner forecast continued rapid growth in Oregon marijuana sales over the next 10 years.

“Our office’s forecast calls for sales to grow approximately 80% over this time period as incomes rise, the state’s population increases, and marijuana becomes more socially acceptable and usage rates rise,” he wrote.

-- Mike Rogoway | mrogoway@oregonian.com | twitter: @rogoway | 503-294-7699

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