The Environmental Protection Agency (EPA) is proposing to approve a state implementation plan (SIP) revision submitted by the State of Tennessee, through the Tennessee Department of Environment and Conservation (TDEC), Air Pollution Control Division, via a letter dated January 23, 2020. The SIP revision includes the 1997 8-hour ozone national ambient air quality standards (NAAQS) Limited Maintenance Plan (LMP) for the Knoxville, Tennessee Area (hereinafter referred to as the ``Knoxville Area'' or ``Area''). The Knoxville Area, as defined in this proposed action, is comprised of Jefferson, Loudon, and Sevier Counties in their entireties, the portion of Cocke County that falls within the boundary of the Great Smoky Mountains National Park, and a portion of Anderson County that excludes the area surrounding TVA Bull Run Fossil Plant. EPA is proposing to approve the Knoxville Area LMP because it provides for the maintenance of the 1997 8-hour ozone NAAQS within the Knoxville Area through the end of the second 10-year portion of the maintenance period. The effect of this action would be to make certain commitments related to maintenance of the 1997 8-hour ozone NAAQS in the Knoxville Area federally enforceable as part of the Tennessee SIP.