as the crow flies

1. The most direct route between two places: “From here to Gold Bar, it's only ten miles as the crow flies, but twenty miles by the winding mountain road.”

Idioms and Phrases

In a straight line, by the shortest route, as in It's only a mile as the crow flies, but about three miles by this mountain road . This idiom is based on the fact that crows, very intelligent birds, fly straight to the nearest food supply. [Late 1700s]