The Environmental Protection Agency (EPA) is approving State Implementation Plan (SIP) revisions, submitted under a cover letter dated June 23, 2017, by the Commonwealth of Kentucky, through the Kentucky Division for Air Quality on behalf of the Louisville Metro Air Pollution Control District (LMAPCD or District or Jefferson County) to EPA, for attaining the 1-hour sulfur dioxide (SO<INF>2</INF>) primary national ambient air quality standard (NAAQS or standard) for the Jefferson County SO<INF>2</INF> nonattainment area (hereafter referred to as the "Jefferson County nonattainment area," "nonattainment area" or "Area"). The Jefferson County nonattainment area is comprised of a portion of Jefferson County in Kentucky surrounding the Louisville Gas and Electric Mill Creek Electric Generating Station (hereafter referred to as "Mill Creek" or "LG&E"). This plan (hereafter called a "nonattainment plan" or "SIP" or "attainment SIP") includes Kentucky's attainment demonstration and other elements required under the Clean Air Act (CAA or Act). In addition to an attainment demonstration, the plan addresses the requirement for meeting reasonable further progress (RFP) toward attainment of the NAAQS, reasonably available control measures and reasonably available control technology (RACM/RACT), base-year and projection-year emissions inventories, enforceable emissions limitations and control measures, nonattainment new source review (NNSR) and contingency measures. EPA concludes that Kentucky has appropriately demonstrated that the nonattainment plan provisions provide for attainment of the 2010 1-hour primary SO<INF>2</INF> NAAQS in the Jefferson County nonattainment area and that the nonattainment plan meets the other applicable requirements under the CAA.