Старинная гостиница «Old Faithful» в Йеллоустоне

The Old Faithful Inn is a hotel in the western United States with a view of the Old Faithful Geyser, located in Yellowstone National Park, Wyoming. The Inn has a multi story log lobby, flanked by long frame wings containing guest rooms. In the western portion of the park, it sits at an approximate elevation of 7350 feet (2240 m) above sea level. With its log and limb lobby and massive (, 85 feet (26 m)) stone fireplace, the inn is an example of the "Golden Age" of rustic resort architecture, a style which is also known as National Park Service Rustic. It is one of the few log hotels still standing in the United States, and was the first of the great park lodges of the American west. Initial construction was carried out over the winter of 1903–1904, largely using locally obtained materials including lodgepole pine and rhyolite stone. When the Old Faithful Inn first opened in the spring of 1904, it boasted electric lights and steam heat. The structure is the largest log hotel in the world; possibly even the largest log building in the world. In 2007 the American Institute of Architects conducted a survey to determine the 150 favorite buildings in America; the Old Faithful Inn ranked 36. The Inn, which was designated a National Historic Landmark in 1987, is itself part of the Old Faithful Historic District. Old Faithful Inn is a member of Historic Hotels of America, the official program of the National Trust for Historic Preservation.

The inn's architect was 29 year old Robert Reamer, an architect for the Yellowstone Park Company, which was affiliated with the Northern Pacific Railway. Reamer was hired by Harry W. Child, the president of the Yellowstone Park Company, who had met Reamer in San Diego through mutual acquaintances. Reamer designed the lobby and the initial phase of guest rooms, known as the Old House, which was built in 1903–1904, much of it in the long winter. The east wing was extended in 1913–14, and the west wing in 1927, creating a single structure almost 700 feet (213 m) long. The Old House is rotated 90 degrees with respect to Old Faithful so that a view of the geyser is framed by the entrance porch for arriving visitors. The porch roof provides a viewing platform for viewing eruptions of Old Faithful and other geysers, while the main facade faces Geyser Hill across the Firehole River, where the old Circuit Road once ran through the geyser basin. The central feature of the Old House is a tall gabled log structure housing the lobby, dominated by a deep, steeply pitching shingled roof. The Old House uses load bearing log lower exterior walls with a log pole interior framework supporting seven stories, six of which are the roof structure. The upper gable walls are of milled lumber framing with shingle sheathing. The front slope of the shingled roof is accented by shed and gabled dormers, some of which are purely decorative. Both interior and exterior framing is supported by twisted or curved branches, giving the entire structure a strongly rustic air. There are two levels of balconies, the lower encircling the lobby and the upper on two sides. Stairs climb from the second balcony to a platform in the framing known as the "Crow's Nest" which once was used by musicians to entertain guests, then on to the crown of the gable 92 feet (28 m) above the lobby floor. The entire structure is crowned by a roof walk that once held searchlights to illuminate Old Faithful Geyser at night. The original guest wings are 3 1/2 stories tall on either side of the lobby. Offset to the southeast corner, the stone fireplace measures 16 feet (5 m) square at the base. It features four main hearths, one on each face, with smaller hearths, each with a flue, at the corners. The stone extends to the roof, and until it was damaged by earthquake, a brick flue extended above the roof, covered in log cribbing. An ironwork clock decorates the north face of the upper chimney in the lobby. Child instead hired Reamer to design a much more radical building with antecedents in the rustic camps of the Adirondacks. Design work took place in 1902, and construction started in 1903, with work continuing through the winter to open in 1904. The original cost of the Inn was about $140,000, using materials gathered from within the park. The hotel was furnished for another $25,000. It was saved by the actions of firefighters, volunteers, and a rooftop sprinkler system installed the previous year. The high range rooms in the East and West wing additions were renovated in 1993 and 1994. In celebration of the Inn's centennial in 2004, a major renovation project of the original "Old House" started construction, with completion in 2008. The project brought the Inn to current building codes and installed new electrical, plumbing, and heating systems, as well as structural upgrades. Finishes were cleaned and restored, maintaining as much of the historic material as possible. Wood and wool floor finishes, bathroom tile and fixtures, new replica historic hardware, and an interpretation of the original lavatory stands and basins by Charles Limbert were installed. Original elements including the recessing of the floor and hearth of the large fireplace in the main lobby and reconstruction of log walls removed in the lobby corrected modifications and changes over the years and brought the Inn back to match more closely Reamer's original design.

Its notable visitors are numerous, even preceding its construction. Chester A. Arthur camped outside the East Wing area in 1883, Theodore Roosevelt visited the site in 1903, Warren Harding stayed in 1923, Calvin Coolidge in 1927, and Franklin Roosevelt in the fall of 1937.

According to park lore, a freak blizzard struck the Old Faithful Inn on August 25 sometime in the early twentieth century. Rather than lament the fact that they were isolated, the guests were said to have taken the opportunity to celebrate Christmas in August.

The Old Faithful Inn was featured in the 1936 film Yellowstone.

The Old Faithful Inn had a pronounced effect on the built environment in North American national parks, influencing the development of the National Park Service Rustic style that became widespread during the 1920s. Although it was not the first hotel with a multi story lobby, the concept became widespread in the mid 20th century in urban hotels.

The Old Faithful Inn was placed on the National Register of Historic Places on July 23, 1973. It is the central element in the Old Faithful Historic District, which includes the Old Faithful Lodge on the other side of Old Faithful. The Lodge, which was designed by Gilbert Stanley Underwood to provide dining and guest services to a community of tent cabins, is lower and more understated in nature, but compatibly rustic.