In 1873 Silver City resident Louis Abraham, a boyhood friend of Henry McCarty, as he was known then, described her as a "Jolly Irish lady, full of fun and mischief." But for being the mother of Billy the Kid, history would probably never know the name of Catherine McCarty. One hundred and twenty-five years later, history still knows precious little about her. What we know of her today comes mainly from interviews with many of her friends and acquaintances in Silver City, New Mexico, where she lived for two years until her death in 1874. Those who visited her household often speak of the hospitality they received and the good home she made for her family. Her world revolved around her two young sons, Joseph and Henry, and on her deathbed, she confided to her nurse Clara Truesdale that she was worried about leaving them in a "wild country". If Catherine McCarty-Antrim had lived beyond her 45 years, history might have changed and the world would have never heard the name of Billy the Kid.

She who gave birth to the Southwest's most celebrated outlaw was herself born in Ireland around 1829. Her surname, parents and siblings, if any, are a complete mystery and may never be known. During the Irish potato famine of 1845, Catherine immigrated to New York City at the tender age of seventeen. A Catherine McCarty is listed on board the passenger ship Devonshire as it departed Liverpool, arriving on American shores April 10, 1846. After her arrival, Catherine found herself all alone in a city overflowing with other immigrants from all over the world, seeking as she did, a better life for themselves. It must have been a terrifying experience for her as she made her way through the streets and back alleys, constantly aware of the numerous thugs loitering in the shadows. For the next several years, Catherine's life and whereabouts are in dispute. We know she gave birth to two sons, Joseph and Henry, aka Billy the kid, probably in New York. Joseph, the older brother, was born in 1854, and died in Colorado on November 25, 1930, at the age of seventy-six. Young Henry, it is thought, was born in 1859. But other questions arise: Who was their father? Did they have different fathers, and if so, what were their names? A number of western historians such as the late Philip J. Rasch and others have endeavored to solve these mysteries of the McCarty genealogy but with only limited success.

The sheer number of Catherine McCarty's listed in the federal census for New York in 1859 makes it virtually impossible to distinguish her from the rest. As noted Lincoln County War historian Frederick Nolan has speculated, Catherine may well have been a "fallen girl", forced to live a life on the streets of New York with two illegitimate children. Sometime after her arrival in New York, Catherine learned she had contracted tuberculosis, or "galloping consumption", as it was called in her day. On the advice of doctors, she moved her family west, taking up residence in southern Indiana around 1866. It was here she would meet William Henry Harrison Antrim, her future husband. Antrim was a veteran of the Union Army and had served with Company "I" of the 54th Regiment of the Indiana Volunteer Infantry as a private until receiving an honorable discharge from service in 1863.

Three years later in 1869, the McCarty family again pulled up their stakes and with help form Mr. Antrim moved to Wichita, Kansas, where Catherine would open and operate a hand laundry service. Antrim, whose property adjoined the McCarty's, turned to farming, carpentry, and tending bar part-time in the local saloons. Once again, Catherine's health began failing her and friends urged her to seek a more arid, dryer climate. With his fortunes fading in Kansas, Antrim had become afflicted with gold fever and informed neighbor Catherine of his plans to journey west to Denver, Colorado, to try his luck at prospecting. She agreed to accompany him. Then, with nothing to show for his efforts in Denver, Antrim brought Catherine and her two sons to Santa Fe in New Mexico Territory, where they stayed with his sister Mary Antrim Hollinger. Up until now, Catherine's relationship with William Antrim seemed cordial enough to allow her to join him in his travels. They had come to know each other well for the last several years, and on March 1, 1873, they were married at the First Presbyterian Church in Santa Fe. The service was ministered by Rev. David F. McFarland and witnessed by a Mr. harvey Edmonds, Mrs. A. R. McFarland, her daughter Katie, and by Catherine's two sons Joseph and Henry. Almost immediately after their wedding, Antrim's ears were filled with rumors of rich silver strikes in the small mining town of Silver City in southwestern New Mexico, and he quickly moved his new family there. In William Antrim's mind, it was all finally coming together for him. He was now living in a log cabin with a new wife and two new stepsons, surrounded near and far by mines with the potential to make a man rich. Catherine spent much of her time making a home for her sons and cooking pies and other assortments which she sold easily to the local citizenry. Years later, boyhood friends of Henry and Joseph would rave about "What a good cook Mrs. Bill Antrim was."

Catherine loved kids, and after school all the neighborhood boys raced for the Antrim cabin where she would greet them with a smile and freshly baked cookies. Although the Antrim household was a happy one, it was far from a prosperous one, as husband William was away most of the time in the mines. For badly needed extra money, Catherine took in boarders from time to time. In 1874, Ash Upson, the newspaperman who would later help Pat Garrett write "The Authentic Life of Billy the Kid", and who later claimed to have written every word, boarded with the Antrim family. Upson wrote of her as, "about medium in height, straight, and graceful in form, with regular features, light blue eyes, and luxuriant golden hair. She was not what the world calls a beauty, but a fine looking woman. A lady by instinct and education." For a time, Catherine's health seemed to on the mend. With an energy unknown to her for some years, she and son Henry joined in the fun at the town bailes (dances) held every week. Louis Abraham remarked that "Mrs. Antrim could dance the Highland Fling as well as the best of the dancers". But during the spring of that year, Catherine was again feeling weak. After treatments of warm sulphur water baths failed to restore her health, Catherine was confined to her bed for the next four months. As she lay in bed gasping for breath and coughing up crimson, Catherine realized she was dying. With her husband gone, her only concern was for the well-being of her two boys. As a last request she asked Clara Truesdale, her nurse, to look after them. Shortly afterwards, on September 16, 1874, Catherine McCarty-Antrim closed her eyes for the last time. She was only 45 years old. Three days later her obituary appeared in the town newspaper, The Silver City Mining Life: