Comprehensive United States history resources for students, covering the period from 1492-1898. The online text is accompanied by videos, interactives such as map makers, reading exercises, online quizzes, printables, and clipart.
Although site is targeted to grades K-8, the US History materials are at a high school reading level. Ads can be intrusive. Authors of site say it will get a makeover in 2018, with a no-ad option.