Samuel Ryan Curtis (February 3, 1805 – December 26, 1866) was an American military officer and one of the first Republicans elected to Congress.

He was most famous for his role as a Union Army general in the Trans-Mississippi Theater of the American Civil War, especially for his victories at the Battles of Pea Ridge in 1862 and Westport in 1864.

During the Mexican–American War, he was appointed colonel of the 3rd Regiment of Ohio Volunteers and served as military governor of several occupied cities.

However, after the Civil War broke out, Curtis was appointed colonel of the 2nd Iowa Infantry on June 1, 1861, prompting him to resign his congressional seat on August 4 of that year.

After organizing the chaos in St. Louis, Missouri, Curtis was given command of the Army of the Southwest on December 25, 1861, by Maj. Gen. Henry W. Halleck.

On the same day in late March that he heard about his promotion, he also found out that his twenty-year-old daughter Sadie died of typhoid fever in St.

In this surprise attack at the Battle of Baxter Springs, Quantrill's men wore Federal uniforms and gave no quarter.

Curtis was then reassigned to a completely different armed conflict, commanding the Army's "Department of the Northwest," which was in the closing phase of a military response to uprisings in southern Minnesota and Dakota Territory by Native Americans against settlers.