By applying our sightability model to surveys conducted around the state, and adding approximate estimates of mountain goat populations for areas we do not survey, we developed an estimate of the total number of mountain goats in the Washington. The total mountain goat population summary.estimate is 2,815, but due to the uncertainty in the sightability estimation and in guessing about areas not surveyed, this may be as low as 2,401 or as high as 3,184. About 25% of these occur in National Parks (Mt. Rainier, North Cascades, and Olympic).