That map seems legit. 
People say "Texas used to include what is now parts of Colorado." That's not exactly how it was. At Independence, the treaty with Mexico mentioned something about the watershed of the Red (I think) river, etc as the boundary for what Mexico agreed to not claim anymore in return for not getting their ass handed to them again. So, the Texans looked and said, "Hey, I think we can claim way up into here" based on this. They sent an expedition up into what is Colorado today, telling the people they found up there: "Hey, ya'll are Texans." The people they found up there told them to go berkeley off. When admitted into the Union (debt and insurance companies factored heavily into that decision), part of the agreement was to not lay claim to the part that is now Colorado.
Look how big the Port of Houston is. You can tell this map is from the 1800s by little things like that being out of proportion.
You'll need to log in to post.
