Question: Battery Steele is a fortification on the island in what Maine city?

Context paragraphs:
Philip J. Deering: Philip J. Deering, Sr. (1878 – December 20, 1935) was an American businessperson and politician from Maine.  Deering, a Democrat, served in the Maine House of Representatives from one term (1910-1912).  He also served four terms as chairman (de facto mayor) of the Portland, Maine City Council in 1924, 1927, 1934 and 1935.

Charles Harlow: Charles W. Harlow (born May 25, 1942) is an American politician from Maine.  Harlow served on the Portland, Maine City Council from 1990 to 1999, including a term as ceremonial mayor from 1992 to 1993.  In 2004, Harlow was elected as a Democrat to the Maine House of Representatives from District 116.  He served until 2010, when he was replaced by his daughter, Denise Harlow.

Battery Steele: Battery Steele (U.S. Army Corps of Engineers Battery Construction #102) is a United States military fortification on Peaks Island, Portland, Maine in Casco Bay.  Completed in 1942 as part of World War II, it is located on 14 acre on the oceanside area of the island, formerly part of the Peaks Island Military Reservation.  It is named for Harry Lee Steele, who was a Coast Artillery officer during World War I.  It was armed with two 16-inch MkIIMI guns and, with a 12-inch gun battery at Fort Levett on Cushing Island, replaced all previous heavy guns in the Harbor Defenses of Portland.  It was built to protect Casco Bay, particularly Portland harbor, from Kennebunk to Popham Beach in Phippsburg.  According to Kim MacIsaac and historian Joel Eastman in "An Island at War", “Battery Steele is not only the largest gun battery built on Peaks Island, but also an example of the largest battery ever built anywhere in the United States.”  In 1995, after decades of non-use, the Peaks Island Land Preserve, a community land preservation group, formed to purchase the area and forever preserve it as a public space.  On October 20, 2005, the property was listed on the National Register of Historic Places.  Other coast defense structures on the island include fire control towers and the counterweight for a disappearing searchlight tower (it "disappeared" when folded down).

Jon Hinck: Jon Hinck (born January 9, 1954) is an American environmentalist, lawyer and politician.  From 2006 to 2012 he served as a member of the Maine House of Representatives, representing House District 118, part of Portland, Maine.  From 2013 through 2016, Hinck held an at-large seat on the Portland, Maine City Council.

Oliver's Battery, Tresco: Oliver's Battery is a ruined artillery battery on the island of Tresco in the Isles of Scilly.  It was built by the Parliamentarian admiral, Sir Robert Blake, after he invaded Tresco in April 1651 during the years of the interregnum.  It was used to bombard the neighbouring island of St Mary's, which was still held by an opposing Royalist army, and forced its surrender several weeks later.  The battery comprised a triangle of ramparts, constructed using earth and rubble, which, combined with the natural stone features on the site, produced a substantial, if crude, fortification.  It is now ruined, and owned by the Duchy of Cornwall.

Battery Gadsden: Battery Gadsden is a historic artillery battery located at Sullivan's Island, Charleston County, South Carolina.  It was built in 1903-1904, and is one of a series of batteries stretching from Fort Moultrie to the eastern end of Sullivan’s Island.  Until decommissioned in 1917, the concrete battery housed four, six inch guns.  It measures approximately 377 feet long and 84 feet wide, with the front or ocean side of the battery at approximately 7 feet high.  Battery Gadsden and its neighbor Battery Thomson provided fortification at the mouth of Charleston Harbor.  The battery now houses the Edgar Allan Poe Branch of the Charleston County Public Library.

Battery Thomson: Battery Thomson is a historic artillery battery located at Sullivan's Island, Charleston County, South Carolina.  It was built in 1906-1909, and is one of a series of batteries stretching from Fort Moultrie to the eastern end of Sullivan’s Island.  Until decommissioned in 1947, the concrete battery housed two, ten inch guns.  It measures approximately 326 feet long and 84 feet wide, with the front or ocean side of the battery at approximately 10 feet high.  Battery Thomson and its neighbor Battery Gadsden provided fortification at the mouth of Charleston Harbor.

Peaks Island: Peaks Island is the most populous island in Casco Bay, Maine.  It is part of the city of Portland and is approximately 3 mi from downtown.  The island became a popular summer destination in the late 19th century, when it was known as the Coney Island of Maine, home to hotels, cottages, theaters, and amusement parks.

Peaks Island Land Preserve: The Peaks Island Land Preserve (PILP) is a non-profit organization concerned with conserving natural land on Peaks Island, Maine for public use.  As of 2013, the PILP managed over 140 acre of land.  It was founded in 1994 to preserve Battery Steele, an historic United States military fortification built on Peaks Island during World War II.  After acquiring Battery Steele, PILP began to obtain land through purchase and donation across the island.  The PILP held its first post-incorporation meeting in 1995 at the Fifth Maine Regiment Community Center.

Santo DiPietro: Santo "Sam" DiPietro (November 11, 1934 – October 9, 2016) was an American businessperson and politician from Maine.  DiPietro, a Democrat, served on the South Portland, Maine City Council for nine years, two of which were as mayor (1986–1987).  He also served four terms (8 years) in the Maine House of Representatives (1989–1996).  In 1988, DiPietro defeated Republican incumbent Earl G. Nicholson to win his seat in the Legislature.

Supporting paragraphs: Battery Steele Peaks Island
Answer: Casco Bay