Question: The southern border of the state in the southern region of the United States represented by Frank Alexander McLain forms what ?

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Roman Catholic Diocese of Rochester: The Roman Catholic Diocese of Rochester is a diocese of the Catholic Church in the Greater Rochester region of New York State in the United States.  The region that the Diocese comprises extends from its northern border on the south shore of Lake Ontario through the Finger Lakes region to its southern border at the New York-Pennsylvania border.

Clintonville, Columbus, Ohio: Clintonville is a neighborhood in north-central Columbus, Ohio, United States with around 30,000 residents.  Clintonville is an informal neighborhood.  The southern border is loosely defined as the center of the Glen Echo Ravine.  To the east, either Interstate 71 or the adjacent railroad tracks are commonly accepted.  The western boundary is the Olentangy River.  The northern border of Clintonville is the most ambiguous, with definitions anywhere in the 3 mi stretch from Cooke Road to the southern border of Worthington.  The Clintonville Area Commission boundaries, as established by Columbus City Code, are "bounded on the south by the centerline of the Glen Echo Ravine; on the east by the centerline of the railroad right-of-way immediately east of Indianola Avenue; on the north by the Worthington city limits and on the west by the Olentangy River; each line extended as necessary so as to intersect with adjacent boundaries".

Canada: Canada ( ; ] ) is a country in the northern part of North America.  Its ten provinces and three territories extend from the Atlantic to the Pacific and northward into the Arctic Ocean, covering 9.98 e6km2 , making it the world's second-largest country by total area and the fourth-largest country by land area.  Canada's southern border with the United States is the world's longest bi-national land border.  The majority of the country has a cold or severely cold winter climate, but southerly areas are warm in summer.  Canada is sparsely populated, the majority of its land territory being dominated by forest and tundra and the Rocky Mountains.  It is highly urbanized with 82 per cent of the 35.15 million people concentrated in large and medium-sized cities, many near the southern border.  Its capital is Ottawa, and its largest metropolitan areas are Toronto, Montreal and Vancouver.

Texas Panhandle: The Texas Panhandle is a region of the U.S. state of Texas consisting of the northernmost twenty-six counties in the state.  The panhandle is a rectangular area bordered by New Mexico to the west and Oklahoma to the north and east. " The Handbook of Texas" defines the southern border of Swisher County as the southern boundary of the Texas Panhandle region, though some consider the region to extend as far south as Lubbock County.  The Texas Panhandle Press Association accepts members in the actual panhandle and a triangle formed by its southern tier, the southeastern border of New Mexico and a diagonal to the beginning, which includes Lubbock County.

Frank A. McLain: Frank Alexander McLain (January 29, 1852 – October 10, 1920) was a U.S. Representative from Mississippi.

Mississippi: Mississippi is a state in the southern region of the United States, with part of its southern border formed by the Gulf of Mexico.  Its western border is formed by the Mississippi River.

United States Border Patrol interior checkpoints: The United States Border Patrol operates 71 traffic checkpoints, including 33 permanent traffic checkpoints, near the southern border of the United States.  The stated primary purpose of these inspection stations is to deter illegal immigration and smuggling activities.  After the September 11 attacks in 2001, they took on the additional role of terrorism deterrence.  These checkpoints are located between 25 and of the Mexico–United States border along major U.S. highways.  Their situation at interior locations allow them to deter illegal activities that may have bypassed official border crossings along the frontier.  The checkpoints are divided among nine Border Patrol sectors.  There are a number of Border Patrol checkpoints in the northern border states (such as New York or Maine), within 100 mi of the Canada–U.S. border.

Miyako Bay: Miyako Bay (宮古湾 , Miyako-wan ) is a bay in Iwate Prefecture, in the northern Tōhoku region of northern Japan.  It is a long and narrow, roughly triangular body of water extending southwest to northeast where it opens to the Pacific Ocean.  The Omoe Peninsula (重茂半島 , Omoe-hantō ) forms its southern border and Cape Anegasaki (姉ヶ崎 , Anegasaki ) forms its southern border.  This gives it an area of approximately 24 km2 .

CSX Southern Region: The CSX Southern Region is a region comprising four divisions in the southern part of the east coast of the United States.  The CSX Southern Region is based in Jacksonville, Florida.

Kordun: The Kordun (] ) region is a part of central Croatia from the bottom of the Petrova Gora (Peter's mountain) mountain range, which extends along the rivers Korana and Slunjčica, and forms part of the border region to Bosnia and Herzegovina.  The southern border of Kordun touches the Lika region.  Most of Kordun with its centre Slunj belongs to Karlovac County (Slunj, Cetingrad, Krnjak, Rakovica and Vojnić).  Vrginmost belongs to Sisak-Moslavina County.  In former times, this region belonged to the Habsburg Military Frontier towards the Ottoman Empire.

Supporting paragraphs: Frank A. McLain Mississippi
Answer: Gulf of Mexico