Question: The Battle of Stones River and Battle of Chickamauga were both fought during what?

Context paragraphs:
Stones River Greenway Arboretum: The Stones River Greenway Arboretum is an arboretum located along the Stones River Greenway, beside the Stones River, in Murfreesboro, Tennessee.

Stones River Campaign: The Stones River Campaign of the American Civil War lasted from November 1862 to January 1863.  The campaign was tactically a draw but was a strategic Union victory due to the Confederate retreat after the Battle of Stones River.

Battle of Stones River: The Battle of Stones River or Second Battle of Murfreesboro, was fought from December 31, 1862, to January 2, 1863, in Middle Tennessee, as the culmination of the Stones River Campaign in the Western Theater of the American Civil War.  Of the major battles of the Civil War, Stones River had the highest percentage of casualties on both sides.  Although the battle itself was inconclusive, the Union Army's repulse of two Confederate attacks and the subsequent Confederate withdrawal were a much-needed boost to Union morale after the defeat at the Battle of Fredericksburg, and it dashed Confederate aspirations for control of Middle Tennessee.

Frederick Phisterer: Frederick Phisterer (October 11, 1836 – July 13, 1909) was an American soldier who fought in the American Civil War.  Phisterer received his country's highest award for bravery during combat, the Medal of Honor.  Phisterer's medal was won for actions at the Battle of Stones River at Murfreesboro, Tennessee, now marked by the Stones River National Battlefield.  He was honored with the award on December 12, 1894.

Joseph Alexander Cooper: Joseph Alexander Cooper (November 25, 1823 – May 20, 1910) was an American farmer, soldier, and civil servant.  A Southern Unionist, he fought for the Union Army during the American Civil War, commanding units at Mill Springs, Stones River, Chickamauga, Franklin, Nashville, Bentonville, and in the Knoxville and Atlanta campaigns.  He had achieved the rank of Brevet Major General by the time he was mustered out in early 1866.

Battle of Chickamauga: The Battle of Chickamauga, fought on September 18–20, 1863 between Union and Confederate forces in the American Civil War, marked the end of a Union offensive in southeastern Tennessee and northwestern Georgia — the Chickamauga Campaign.  It was the first major battle of the war fought in Georgia, the most significant Union defeat in the Western Theater, and involved the second-highest number of casualties after the Battle of Gettysburg.

Stones River National Battlefield: Stones River National Battlefield, a 570 acre park along the Stones River in Rutherford County, Tennessee, three miles (5 km) northwest of Murfreesboro and twenty-eight miles southeast of Nashville, memorializes the Battle of Stones River, a key battle of the American Civil War that took place on December 31, 1862 and January 2, 1863, which resulted in a strategic Union victory.

Paysonia stonensis: Paysonia stonensis (syn.  "Lesquerella stonensis") is a species of flowering plant in the mustard family, known by the common name Stones River bladderpod.  It is endemic to Tennessee in the United States, where it is limited to Rutherford County.  It grows only in the floodplains of the Stones River, and certain tributaries.

11th Michigan Volunteer Infantry Regiment: The 11th Michigan Volunteer Infantry, initially known as Colonel May’s Independent Regiment, was a unit in the Union army during the American Civil War.  The regiment fought with the Army of the Cumberland in numerous battles, including Stones River, Chickamauga, and Missionary Ridge.

21st Ohio Infantry: The 21st Ohio Volunteer Infantry was an infantry regiment in the Union Army during the American Civil War.  Mostly an all-volunteer unit, with the exception of a few draftees, the 21st Ohio served for both ninety-day and three-year enlistments and fought exclusively in the Western Theater.  It saw action in some of the war's bloodiest battles including Stones River, Chickamauga, the Atlanta Campaign, and Sherman's March to the Sea.

Supporting paragraphs: Battle of Stones River Battle of Chickamauga
Answer: Civil War