Such was the extent of the United States when Lincoln began his political life.  In the movement of population by which this domain was being settled up, different streams may be roughly distinguished.  First, there was from 1780 onwards a constant movement of the poorer class and of younger sons of rich men from the great State of Virginia and to some extent from the Carolinas into Kentucky and Tennessee, whence they often shifted further north into Indiana and Illinois, or sometimes further west into Missouri.  It was mainly a movement of single families or groups of families of adventurous pioneers, very sturdy, and very turbulent.  Then there came the expansion of the great plantation interest in the further South, carrying with it as it spread, not occasional slaves as in Kentucky and Tennessee, but the whole plantation system.  This movement went not only directly westward, but still more by the Gulf of Mexico and up the Mississippi, into the State of Louisiana, where a considerable French population had settled, the State of Mississippi, and later into Missouri.  Later still came the westward movement from the Northern States.  The energies of the people in these States had at first been to great extent absorbed by sea-going pursuits and the subjugation of their own rugged soil, so that they reached western regions like Illinois rather later than did the settlers from States further south.  Ultimately, as their manufactures grew, immigration from Europe began its steady flow to these States, and the great westward stream, which continuing in our days has filled up the rich lands of the far North-West, grew in volume.  But want of natural timber and other causes hindered the development of the fertile prairie soil in the regions beyond the upper Mississippi, till the period of railway development, which began about 1840, was far advanced.  Illinois was Far West in 1830, Iowa and Minnesota continued to be so in 1860.  The Northerners, when they began to move westward, came in comparatively large numbers, bringing comparatively ordered habits and the full machinery of outward civilisation with them.  Thus a great social change followed upon their arrival in the regions to which only scattered pioneers such as the Lincolns had previously penetrated.  In Illinois, with which so much of our story is bound up, the rapidity of that change may be estimated from the fact that the population of that State multiplied sevenfold between the time when Lincoln settled there and the day when he left it as President.

The concluding stages by which the dominions of the United States came to be as we know them were:  the annexation by agreement in 1846 of the Republic of Texas, which had separated itself from Mexico and which claimed besides the great State of Texas a considerable territory reaching north-west to the upper portions of the Arkansas River; the apportionment to the Union by a delimitation treaty with Great Britain in 1846