Land, and with it opportunity. At a time when family's were large, and most family's were poor, the promise of land - tough as it was to break the sod and settle - was a great draw to people who were faced with either splitting their father's farm with 10 or 12 siblings, not inheriting at all, or working for someone in a menial task their entire life. Knowing this helps you better understand why many took the risks they took. It also explains (not excuses) why people on the frontier weren't always the most civil people in the nation.