Facts and Events
It is likely that Ann married Samuel Cowan c1766 in Orange Co., NC. Her parents are known to have been living there at the time. Data is needed that places Samuel Cowan's family there. There is a possibility that Ann married Samuel while her parents were living on Borden's Grant (modern Rockbridge), though there is little evidence to support that. About 1771 the Cowan's and Walkers settled in the Castle's Woods area in Southwest Virginia. Samuel's brother William is belived to have married Ann's sister Jane in Castles Woods about this time. It is reasonable that the marriage between Samuel and Ann occurred at the same time, and that the Cowan's were never in Orange County, NC.
Samuel was killed in 1776 while attempting to warn the settlers at Houston's Fort of a forth coming Indian attack. Ann's brother John Walker IV was living there at the time, and the Fort was established by one of her mother's nephew's.
The following year Ann was captured by Indians during a raid on the Castle's Woods settlement. Her brother Samuel Walker was killed at this time, and her nephew William Walker, son of John Walker IV, was also taken. While it is commonly said that Ann was held captive for seven years, eyewitness testimony has her being returned by 1780, indicating that her captivity lasted no more than three or four years. We have no further direct records for her, but relative Thomas Carter would later write that she would tell the family that on the night of her capture the Indians lost four men during their raid. That may indicate that she returned to the Castle's Woods area; otherwise this information would probably not have been known to Carter.
Carter's account of Ann's capture, though cursory, also suggests that she had two infant children at the time. One of those would be her son, John Cowan, who reached adulthood around 1785, in Castle's Woods. Possibly Ann went to live with him, though it is more likely that she lived with one of her husbands family, perhaps William Cowan who lived in Castle's Woods, where Samuel and Ann owned land. In any case, most of her remaining family, both the Walkers and the Cowan's, left the Castle's Woods area about 1785, settling in Kentucky, and Tennessee. This includes her son John Cowan who seems to have left the area by about 1785, and we presume that Ann went with him. Andrew Cowan, another of Ann's brotherinlaws, remained in the Castle's Woods area at least until 1793, and one of his sons, Andrew Jr., married and settled down locally as well.
Where John Cowan settled is not known.  Some have identified him as the John Cowan (aka Major John Cowan) who married Agness Martin in 1788 in Green County, TN, later Blount County, TN. While possible, Major John Cowan is more commonly identified as the son of Robert Cowan and Susan Woods, not Samuel Cowan, and Ann Walker. Another possibility is that this John Cowan returned to his mothers family in Rockbridge Co, VA. This interpretation is largey based on the testimony of Mrs. Blaine as cited in Fleming, 1971:364. Under that view this is the John Cowan (1768-1832) who married Margaret Weir 91776-c1813) in 1793 in Rockbridge Co, VA Morton, 1973:479, and subsequently moved to Crawfordsville, Montgomery County, IN by 1813. This is consistent with the idea that John son of Samuel dissappears from the records of SW VA about 1785, and may explain his apparent absence in TN. It may also explain why we have no further evidence for Ann Walker Cowan, assuming she relocated with him.
Unfortunately, direct evidence for the fate of both Ann and her son John, are very limited, and their ultimate fate can not be stated with any certainty.