William Menger died in 1871, leaving his wife Mary and their son Louis William to run both the hotel and the brewery. Mary wasted no time. She placed an announcement in the local newspaper declaring that her husband's death 'would cause no change in affairs' at either business. She bought neighboring land, built new rooms, and hosted more than 2,000 guests in a single year. She was also the hotel's chief cook, preparing menus of soups, beef, pasta, veal, and desserts served at a single sitting. The Mengers purchased the finest beef, chicken, butter, and eggs at local markets, and sent a wagon with benches around town to pick up businessmen and drive them to the hotel for dinner. When the first passenger train steamed into San Antonio on February 19, 1877, Mary was ready for the surge. She installed gas lighting by 1879, added modern bathrooms and room service bells, and put a mail chute on every floor. But age caught up with her, and Louis had no interest in the business. On November 7, 1881, she sold the hotel to its original contractor, J. H. Kampmann, for $118,500.

Kampmann and his son Hermann transformed the Menger over the next decades. They added an east wing, relocated the kitchen, expanded the dining room to seat 160, and piped water to every room for private bathrooms -- a luxury almost no other hotel offered at the time. Hermann reportedly sent an architect to study the House of Lords club bar in London to build a replica inside the Menger. In 1887, the new saloon opened with ornate mahogany tables and chairs, large mirrors, fine crystal, and sterling silver. In 1909, architect Alfred Giles gave the hotel a French facade, marble lobby floors, patterned tile in the Victorian lobby, and Corinthian columns around an oval-shaped entrance hall. Architect Atlee B. Ayres added 30 guestrooms and renovated the dining room in 1912. For a time, the Menger was the most elegant hotel in San Antonio. But after World War I, the Kampmann family could no longer finance large social events. By 1929, the hotel had been dropped from state guidebooks. The Great Depression starved it of guests and revenue, and during World War II, plans circulated to demolish it and pave the site for parking.

William Lewis Moody Jr. bought the Menger in 1943, and his National Hotel Corporation took possession on June 30, 1944. After the war ended, Moody launched a complete restoration. By 1948, new plumbing and electrical fixtures were installed, the Spanish patio gardens were restored, guestrooms were renovated, and $100,000 went into a new kitchen. Local artist Ernst Raba restored the artworks, antique furniture was refinished and reupholstered, and the Colonial Dining Room was brought back to life. Many of Mary Menger's original recipes are still served there today, and the mango ice cream remains a guest favorite. The hotel was added to the National Register of Historic Places in 1976 as a contributing building in the Alamo Plaza Historic District. It is a member of Historic Hotels of America, a program of the National Trust for Historic Preservation.

What makes the Menger unlike any other hotel in America is its address. It sits directly on the site of the Battle of the Alamo, in the Alamo Plaza Historic District alongside the Alamo Mission itself. The Crockett Hotel, built in 1909 and also owned by the Menger's parent company, stands across the street. The hotel served the Confederacy during the Civil War, shutting down its guestrooms to house soldiers and keeping the dining room open to feed military personnel and tend wounded. It has weathered every transformation of San Antonio, from frontier cattle town to modern military metropolis. Today the Menger is owned by Galveston-based 1859 Historic Hotels, Inc., and the name is no accident -- 1859 is the year William Menger opened his doors because his brewery customers needed somewhere to sleep.