From California to Oregon, these counties are some of the most profitable in America's housing market, and proves that the investment was definitely worth the money.

Catey Hill of MarketWatch writes in 2015 home sellers made a 49% or better return on their investment. The most profitable county is San Mateo County, Calif, where home sellers saw a 65% increase between the price they paid for the home and the price when they sold it. Other profitable counties include, Alameda County, Calif., Santa Clara County, Calif, Middlesex County, N.J., and Multnomah County, Ore.

The main reason sellers saw such large profits is that the area is popular with tech executives and high-paid employees, says Daren Blomquist, the vice president of RealtyTrac.

For the country as a whole, sellers in 2015 realized an 11% gain (or an average of $20,378 profit) in sale price compared with purchase price. And homeowners sold at a loss in just 19 of the 155 markets examined by RealtyTrac.

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