Here's why:

* Location: Fort Kearny was located in present-day Kearney, Nebraska.

* Continental Divide: The Continental Divide runs through the Rocky Mountains and separates the watersheds that drain to the Atlantic Ocean from those that drain to the Pacific Ocean.

* Geography: Nebraska is located east of the Rocky Mountains and therefore east of the Continental Divide.

Therefore, Fort Kearny, being in Nebraska, is east of the Continental Divide.