"United States Census, 1850," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MXQ7-MWL : 12 April 2016), Alice Pendleton in household of George Pendleton, Cincinnati, ward 1, Hamilton, Ohio, United States; citing family 691, NARA microfilm publication M432 (Washington, D.C.: National Archives and Records Administration, n.d.).
Find A Grave, database and images (https://www.findagrave.com : accessed 17 September 2018), memorial page for Mary Alicia “Alice” Key Pendleton (20 Nov 1824–20 May 1886), Find A Grave: Memorial #94098654, citing Woodlawn Cemetery and Conservancy, Bronx, Bronx County, New York, USA ; Maintained by Find A Grave (contributor 8) .
I'm surprised you don't have more on this woman. I'm more closely connected to her father than today's "See how closely connected you are" would indicate. Mary Alicia Keys married George Hunt Pendleton, vice presidential candidate in the doomed campaign of George McClellan against Abraham Lincoln. George Hunt Pendleton is a distant cousin of mine. George Hunt Pendleton was a son of Nathaniel Greene Pendleton and Jane Frances Hunt. Nathaniel Greene Pendleton was the son of Nathaniel Pendleton and Susan Bard. Nathaniel Pendleton was the son of Nathaniel Pendleton and Elizabeth Clayton. Nathaniel Pendleton was a son of Henry Pendleton and Mary Bishop Taylor, and thus brother of Judge Edmund Pendleton.