Common Lit is a newer website and it has historical documents along with informational text. There are also special features to help lower level students as well. It is called Guided Reading Mode.
It has short informational text articles that students can read. The articles are of high interest and often relate to current events that are happening in the world. A nice feature is being able to select the grade level and the CCSS that you want to assess.
When you create your class roster, each student will take an 8 question pretest that will help assess your students' reading levels. As students take the quiz, depending on if the questions are answered correctly or not, the quiz adjusts to your students' levels. Once a students' level is determined, s/he is given informational text passages to read and answer questions. If a student gets a question wrong, it is explained why the answer was wrong which is a great feature. This site would be great for individualization when not meeting in guided reading groups. There is a great teacher component where you can see the students' data on the quizzes and see if their reading levels are moving up, going down or staying the same.
It does a great job of finding informational text articles that relate to many different areas in both science and social studies. For example, there are many articles on Westward Expansion, Civil War, Slavery and so many more. The great thing about this site is that you can select a grade level or lexile level and many articles can be written at different levels so you can use them for guided reading groups.