About NCMA. NCMA is the national trade association representing the producers and suppliers of concrete masonry products, including concrete block, manufactured stone veneer, segmental retaining walls and articulating concrete block. For over 100 years, the Associationâs mission remains to advance, protect and promote the common interests of its members.
Between 1803 and 1853, the United States almost tripled in size. In the early 1800s, the land west of the United States was very undeveloped.
Westward Expansion: The Louisiana Purchase. 1  One of the first colored illustrations to be put into print, John H.B. 2  Thomas Jefferson's purchase of the Louisiana Territory in 1803 â over 600 million acres at less than 4Â¢ an acre â was an economic as well as a political victory, as it avoided a possible war with the French. The Louisiana Purchase demonstrates Jefferson's ability to make pragmatic political decisions.