Alexander G. Clark (February 25, 1826 – May 31, 1891) was an African-American businessman and activist who served as United States Ambassador to Liberia in 1890–1891, where he died in office. In 1867 Clark sued to gain admission for his daughter to attend a local public school in Muscatine, Iowa. The case of Clark v. Board of School Directors achieved a constitutional ruling for integration from the Iowa Supreme Court in 1868, 86 years before the United States Supreme Court decision of Brown v. Board of Education (1954). He was a prominent leader in winning a state constitutional amendment that gained the right for African Americans in Iowa to vote (1868). Active in church, freemasonry, and the Republican Party, he became known for his speaking skills and was nicknamed "the Colored Orator of the West." He earned a law degree and became co-owner and editor of The Conservator in Chicago. His body was returned from Liberia in 1892 and buried in Muscatine, where his house has been preserved.

Alexander G. Clark was born February 25, 1826, in Washington, Pennsylvania to parents who had been freed from slavery. His parents were John Clark and Rebecca (Darnes) Clark. When he was around 13, Clark moved to Cincinnati, Ohio, to live with an uncle and learn the barbering trade. His uncle, William Darnes, also saw to his education in other areas. Two years later the young Clark started working on the river steamboat George Washington.

In May 1842 at age 16 Clark settled in Muscatine, Iowa (then known as Bloomington), the Mississippi River town where he made his life. He worked as a barber and became an entrepreneur, acquiring real estate and selling timber as firewood to the steamboats that frequented the Mississippi River. Barbering was a service trade that helped him meet influential whites in town as well as blacks.

During the next two decades, this area along the Mississippi River was a destination for other African Americans. Located 90 miles upriver of the border of the slave state of Missouri, Muscatine attracted the largest black population in the state: 62 in 1850, with hundreds more by 1860. Some blacks settled there after fleeing the South via the river as fugitive slaves; others came from eastern free states. Quakers and other religious groups supported abolitionism.

Having gotten established, Clark married Catherine Griffin of Iowa City on October 9, 1848. She had been freed from slavery in Virginia at age 3. The Clarks had five children, two of whom died in infancy. Their surviving children were Rebecca, Susan, and Alexander G. Clark Jr.

Also in 1848 Clark was among the 34 founding members of the local African Methodist Episcopal Church in Muscatine, helping buy land for their first building, which was completed the next year. The AME church was the first independent black denomination in the United States, founded in Philadelphia, Pennsylvania in the early 19th century.

Clark became acquainted with abolitionist Frederick Douglass and was the Iowa agent for the Douglass newspaper The North Star. He reportedly attended a Douglass-organized convention in Rochester, New York, in 1853. They were still in touch in the late 1880s, and some of their correspondence was published in newspapers.

In 1863, during the American Civil War (1861–1865), Clark helped recruit the "60th Iowa Colored Troops, originally known as the 1st Iowa Infantry, African Descent." Despite being a small minority in the state, by war's end, a total of nearly 1,100 blacks from Iowa and Missouri served in the regiment. Clark enlisted at age 37 and was ranked as sergeant-major, but he could not muster due to a physical defect, perhaps in his left ankle.