Fondly remembered as "Old Uncle Dennis" or "Father Pennington," he was known for his common sense and strong character and became one of Harrison County's most influential citizens.

[4] In the fall of 1797 Pennington moved west to Kentucky, traveling part of the way with anti-slavery advocate Henry Clay.

William and Virginia Pennington settled near present-day Lanesville, Indiana, a part of the Northwest Territory at that time.

[8] Pennington arrived in Harrison County around 1802, purchased land near Lanesville, where his brother, William resided with his family, built a homestead, and established a farm.

On December 28, 1802, Harrison asked the U.S. Congress for a ten-year suspension of Article VI of the Northwest Ordinance of 1787 that prohibited slavery in the territory.

The meeting attendees drafted and adopted a resolution opposing slavery in the territory and resolved to put an end to the "despised institution".

[17] Pennington also supported the doctrine of "squatter sovereignty," which would grant citizens the right to decide the future of slavery in the territory.

[14] On February 27, 1809, the U.S. Congress amended the Northwest Ordinance to allow the Indiana Territory's citizens to elect representatives to its bicameral legislature, which reduced the governor's power.

[20] Shortly after the outbreak of the War of 1812, Pennington wrote a resolution to relocate the territorial capital:[21] "Resolved, that the capitol be removed from Vincennes, because it is dangerous to continue longer here on account of threatened depredations of the Indians, who may destroy our valuable records.

"[22] Corydon, Pennington's hometown, competed with Charlestown, Clarksville, Jeffersonville, Lawrenceburg, and Madison, to become the new territorial capital.

Pennington was awarded the contract to supervise construction of the new courthouse, which began in 1814 and was nearly completed when Indiana's first state legislature convened at Corydon in 1816.

[26][27] On March 3, 1813, Thomas Posey succeeded Harrison as governor of the Indiana Territory and head of the pro-slavery party.

Pennington continued to attack the territory's pro-slavery faction and, according to some sources, his unrelenting political assault drove Posey from the capital at Corydon.

Pennington and other members of the anti-slavery movement tried to prevent slavery from becoming a part of Indiana's state constitution, which would be drafted in June 1816.

[4][33] Pennington was present when the delegates convened at Corydon from June 10 to 29, 1816, to consider statehood and to draft fIndiana's first state constitution.

[29] As outlined in Article VIII, Section 1, Indiana's 1816 constitution banned any alteration or amendment of the state constitution that would introduce slavery or involuntary servitude into the state: But, as the holding any part of the human Creation in slavery, or involuntary servitude, can only originate in usurpation and tyranny, no alteration of this constitution shall ever take place so as to introduce slavery or involuntary servitude in this State, otherwise than for the punishment of crimes, whereof the party shall have been duly convicted.

[3] During the campaign and as one of the most outspoken members of the Indiana General Assembly, Pennington opposed the state's massive plan for internal improvements, especially the construction of the Wabash and Erie Canal.

[citation needed] The entire system of internal improvements, which included a network of roads, canals, and railroads, was never fully completed and the massive projects bankrupted the state government.

Instead of receiving repayment in cash, some creditors accepted stock in the Wabash and Erie Canal, which eventually covered 468 miles (753 km).

[4] Pennington is best known for his opposition to slavery and years of public service representing Harrison County as a territorial and state legislator.

Beginning in 1810 he served speaker of its lower house of representatives and helped secure Corydon's selection as the new seat of government in 1813.

[43] The Kintner House Inn, a bed and breakfast in Corydon, Indiana, named one of its guest rooms in honor of Pennington, one of Harrison County's most influential citizens.