Lyman Trumbull House

The Haskell Playhouse is a children's playhouse located in Haskell Park in Alton, Illinois. Dr. William Abraham Haskell, a physician and one of the wealthiest residents of Alton, commissioned the playhouse as a present for his daughter Lucy's fifth birthday in 1885. Architect Lucas Pfeiffenberger designed the playhouse in the Queen Anne style. The house's design features a raised front porch with a projecting entrance, diagonal stickwork on the porch and first floor, and fishscale shingles on the second-story gable ends. An ornamental iron fence with a small spire tops the house's hipped roof. Lucy Haskell died of diphtheria four years after her playhouse was built, and by 1916 her mother Florence (Hayner) Haskell was the only surviving Haskell still living in Alton. Florence demolished the family's home that year but kept the playhouse as a memorial to her daughter; she donated the land to the city to serve as a memorial park.The playhouse was added to the National Register of Historic Places on July 30, 1974.

The Middletown Historic District is a historic district in Alton, Illinois. The primarily residential district includes portions of Alton's Middletown and Hunterstown neighborhoods and comprises 653 buildings, 613 of which are contributing buildings. Settlement in the district dates to the original plat of Alton in 1817, which included the southern half of Middletown. Development in the district continued through the 19th century and into the 20th, spanning all of Alton's early history. The district also represents multiple eras of Alton's architectural history. Most early houses in the district were designed in the Federal style, while the Italianate and Queen Anne styles were predominant in the latter half of the 19th century.The district was added to the National Register of Historic Places on July 11, 1978. in 1982, the boundaries of the district were expanded to include Alton's Pagan Hill neighborhood. In January 2022, the boundaries were expanded again and now take in most of downtown Alton. The expanded area includes 134 new properties covering 11 blocks in the downtown area stretching from State Street to Ridge Street along Third Street, Broadway, and Front Street/Landmarks Boulevard.

The Guertler House is a historic house located at 101 Blair St. in Alton, Illinois. Stonemason Ignaz Bruch built the house in 1854. Bruch, who immigrated to the United States from Germany in 1846, was a prominent Illinois stonemason who constructed buildings in cities ranging from Chicago to St. Louis, Missouri. The Guertler House is a Federal building with three bays. The front door and windows have a pointed arch design, while the second story of the house's west side has a single Gothic arch window.The house was added to the National Register of Historic Places on July 30, 1974.

Marquette Catholic High School is a private, Catholic high school in Alton, Illinois. It is located in the Diocese of Springfield in Illinois.

The Hotel Stratford is a historic hotel located at 229 Market St. in Alton, Illinois. The hotel, originally known as the Illini Hotel, opened in 1909. St. Louis architectural firm Barnett, Haynes & Barnett designed the hotel in the Classical Revival style. The five-story brick building features brick quoins, limestone bands and window sills, terra cotta ornamentation, and a cantilevered cornice. The hotel opened a rooftop garden in 1910 and a reception room in 1912, and it became one of many hotels which drew conventions to Alton; a contemporary newspaper account described the building as part of the "greatest improvement in property in the city of Alton". In 1925, new owner E. J. Lockyer renamed the hotel to its current name. The hotel is the only hotel built in Alton before 1950 that is still in operation.The hotel was added to the National Register of Historic Places on January 27, 2000.

McPike Mansion, or Mount Lookout, is a mansion in Alton, which is part of the Metro-East region of the Greater St. Louis metropolitan area in the U.S. state of Illinois. Built in 1869 by Henry Guest McPike (1825–1910), it is situated on Alby Street on a site of 15 acres (61,000 m2), one of the highest points in Alton, which was called Mount Lookout.

The Elijah P. Lovejoy Monument, also known as the Elijah Lovejoy Monument, Elijah Parrish Lovejoy Shaft, Lovejoy Monument, and Lovejoy State Memorial, is a memorial in Alton, Illinois to Elijah P. Lovejoy, an advocate of free speech and the abolition of slavery. Lovejoy had moved his press across the Mississippi River to Alton after his offices were attacked three times by pro-slavery forces at his former location in St. Louis, Missouri. He hid the press in a warehouse before setting up his new operation but was attacked again on November 7, 1837. He was fatally shot that night when the building was attacked and destroyed by a pro-slavery mob.

The Yakel House and Union Brewery are a historic house and brewery complex located at 1421-1431 Pearl St. in Alton, Illinois. Philip Yakel, a German immigrant, built the brewery soon after coming to America in 1836. The brewery was the first in Alton and one of the city's earliest successful industries. Yakel's son George, who eventually ran the brewery alongside his father, built the house in 1863; it was the family's second home at the site. The brick home features a vernacular design influenced by German architectural tradition. William Netzhammer, a brewer from St. Louis, purchased the brewery in 1882. The Netzhammer family ran the brewery until it closed in 1952;, notably, the brewery continued production during Prohibition by making near beer.The complex was added to the National Register of Historic Places on May 11, 1982.

Lock and Dam No. 26 was a lock and dam located near Alton, Illinois on the Upper Mississippi River around river mile 202.5. Opened in 1938, its largest lock was 600 feet long. It was demolished in 1990 and replaced by the Melvin Price Locks and Dam, which is also known as Lock and Dam number 26.

Alton National Cemetery is a United States National Cemetery located in the city of Alton, in Madison County, Illinois. Administered by the United States Department of Veterans Affairs, it encompasses only half an acre plot of land, and as of the end of 2005, had 522 interments. It is maintained by the Jefferson Barracks National Cemetery, in St. Louis, Missouri.

The Alton Chapter House is a historic building located at 509 Beacon St. in Alton, Illinois. The building was constructed between 1909 and 1910 as a meetinghouse for Alton's chapter of the American Woman's League. The American Woman's League was a political and social organization founded by magazine publisher Edward Gardner Lewis in 1908. The organization was created to promote feminist causes, particularly the women's suffrage movement; Lewis also intended for the organization to promote and sell his women's magazines. Lewis commissioned the St. Louis architectural firm of Helfensteller, Hirsch & Watson to design five classes of buildings which the League would use as meetinghouses. The Alton Chapter House is an example of a Class II building, which was designed for clubs with 60 to 100 members. The building was designed in the Prairie School style and cost $2,500. After the club disbanded, the building was converted to a private home.The building was added to the National Register of Historic Places on November 28, 1980. It is one of nine American Woman's League chapter houses on the National Register in Illinois.

The Alton Bridge was a railroad bridge that carried the Chicago, Burlington, and Quincy (later Burlington Northern) across the Mississippi River between West Alton, Missouri, and Alton, Illinois. It was located 100 yards (91 m) upriver from, and parallel to, the Old Clark Bridge. The bridge was built between 1892 and 1894 and was removed shortly after the line was abandoned in 1988. With a total length of 2,060 feet (630 m), it consisted of eight through-truss segments—six Pratt trusses, one Pennsylvania truss, and one pivot-swinging truss.