This Land Is Our Land Act This bill prohibits the Department of Homeland Security from constructing, or obligating or expending any funds for the construction of, any new border barriers, including walls or fences, on federal lands under the jurisdiction of the Department of the Interior or the Department of Agriculture (USDA) within 100 miles of the international land borders of the United States. The bill prohibits the President from obligating or expending funds for the construction of any new border barrier, including walls or fences along the border between the United States and Mexico, pursuant to a declaration of a national emergency. The bill declares that any authorization to exercise, in the name of the United States, the right of eminent domain, shall have no force or effect, to the extent that the purpose is the construction of any new border barriers, including walls or fences, on federal lands under the jurisdiction of Interior or USDA within 100 miles of the international land borders of the United States.