The Great Cove massacre was an attack by Shawnee and Lenape warriors led by Shingas, on the community of Great Cove, Pennsylvania (sometimes referred to as Big Cove, modern day McConnellsburg, Pennsylvania in what was, at the time, Cumberland County) on 1 November 1755, in which about 50 settlers were killed or captured. Following the attack, settlers returned to the community to rebuild, and the Provincial Council of Pennsylvania began constructing a chain of forts and blockhouses to protect settlers and fend off further raids. These forts provided an important defense during the French and Indian War.

The communities of Great Cove, Little Cove (Franklin County) and the Conolloways were probably settled soon after 1730 by Scotch-Irish immigrants. The land at that time was still recognized as belonging to Native Americans, but settlers set up homesteads and cleared the land without seeking formal ownership, in spite of "frequent prohibitions on the part of the government and admonitions of the great danger they run of being cut off by the Indians, as these settlements were on lands not purchased of them." In 1742, the Six Nations Iroquois Confederacy lodged a formal complaint, and settlers were warned against establishing homesteads in the area, but they continued to do so. In May 1750, 62 settlers living illegally on the Aughwick, Licking Creek and at Great Cove were convicted of trespassing and forcibly expelled by Provincial government authorities. The commission overseeing the expulsion included Conrad Weiser, Richard Peters, George Croghan and Sheriff John Potter of Cumberland County. Eleven cabins were burned in Path Valley, and three cabins were burned in Great Cove. The area was subsequently referred to as Burnt Cabins, Pennsylvania. Nonetheless, settlers returned to the area and reestablished their communities. Within a few months of burning the cabins, Richard Peters wrote to Conrad Weiser that "The People over the Hills are combin'd against the Government, [and] are putting in new Cropps and bid us Defiance." On the date of the massacre, 93 families are known to have resided in Great Cove, Little Cove, and the Conolloways.

Following General Edward Braddock's defeat on 9 July 1755 at the Battle of the Monongahela, at the beginning of the French and Indian War, Pennsylvania was left without a professional military force. Lenape chiefs Shingas and Captain Jacobs launched dozens of Shawnee and Delaware raids against British colonial settlements, killing and capturing hundreds of colonists and destroying settlements across western and central Pennsylvania. The nearby settlement of Penn's Creek was destroyed by Lenape warriors on 16 October.

On 1 November 1755, a band of about 100 Lenape and Shawnee warriors, and possibly a few French soldiers, launched attacks on the Great Cove settlement and a neighboring settlement known as the Conolloways, with the force splitting into two groups of 50 just before the assault. The Lenape chief Shingas is known to have participated, and also Captain Jacobs. At least one source states that the Lenape leader Tamaqua also took part in the attack. Some of the settlers received advance warning of the attack, reportedly from a settler named Patrick Burns who had escaped from captivity among the Indians, and about half of those living in the two communities fled.

On 2 November, The Pennsylvania Gazette reported:

In a letter written on 2 November, Sheriff Potter gives an account of the attack and describes his efforts to pursue the Indians, stating that he took 40 men into the community but did not encounter any of the attackers. Later they were joined by "a recruit" of 60 men and "held counsel whether to pursue up the valley all night or return to McDowell's, [but]...there were not six of these men that would consent to go in pursuit of the Indians." On 6 November, Adam Hoops wrote to Governor Robert Morris that Captain Hance Hamilton was arriving from York County with 200 men and that another 200 men from Lancaster County were prepared to fight. Pennsylvania militia searched the area but lost the trail in the newly-fallen snow, although they found the body of a child, probably killed because he or she was unable to keep pace with the fleeing warriors.

No definitive account of the number of casualties exists, although a Pennsylvania Gazette article published on 13 November names seven of those killed and eighteen taken captive, 11 of whom were children. Sheriff Potter testified on 14 November to provincial authorities that "of ninety-three families which were settled in the two coves and the Conolloways, forty-seven [persons] were either killed or taken [prisoner]." In his letter of 6 November, Adam Hoops reported "about fifty persons killed or taken."

Captives taken during the raid were escorted back to Kittanning, a Lenape community that served as a staging area for raids on Pennsylvania settlements. Captain Jacobs told the Flemings that captives would be resettled as slaves among Native American communities sympathetic to the French in the Ohio Country, but some captives were taken to Canada and sold to the French there. At least one captive is known to have escaped near Oswego, New York in September, 1756. Three captives were released by the Lenape chief Tamaqua at the Lancaster Council of August 1762, and several others were handed over to Colonel Henry Bouquet at his camp on the Muskingum River in November 1764.