According to the United States Census Bureau, Eagle has a total area of 24.0 km² (9.3 mi²). 23.8 km² (9.2 mi²) of it is land and 0.2 km² (0.1 mi²) of it is water. The total area is 0.97% water ( Eagle is on the Boise River ).

There are 3,864 households out of which 45.9% have children under the age of 18 living with them, 69.4% are married couples living together, 7.6% have a female householder with no husband present, and 19.8% are non-families. 16.1% of all households are made up of individuals and 5.3% have someone living alone who is 65 years of age or older. The average household size is 2.87 and the average family size is 3.23.
In the city the population is spread out with 32.6% under the age of 18, 5.6% from 18 to 24, 31.1% from 25 to 44, 23.1% from 45 to 64, and 7.6% who are 65 years of age or older. The median age is 35 years. For every 100 females there are 100.7 males. For every 100 females age 18 and over, there are 95.5 males.

For more official information about Eagle, please visit the following web-sites.

City of Eagle - The official web-site for Eagle Idaho.