Atlanta is the capital and the largest city in the U.S. state of Georgia, with a population of 519,145, and the core city of the ninth most populous United States metropolitan area, at 5,278,904, with a combined statistical area population of 5,626,400. The Atlanta metropolitan area is the fastest growing area in the nation since 2000 when measured by numerical increase, is the central metropolis of the Southeastern United States, and is the largest metropolitan area in the emerging megalopolis known as the Piedmont Atlantic MegaRegion. Atlanta is the county seat of Fulton County, although a small portion of the city extends into DeKalb County. Residents of the city are known as Atlantans.

According to the United States Census Bureau, the city has a total area of 343.0 km2 (132.4 sq mi). 341.2 km2 (131.7 sq mi) of it is land and 1.8 km2 (1 sq mi) of it is water. The total area is 0.51% water. At about 1,050 feet (320 m) above mean sea level (the airport is at 1,010 feet (308 m)), Atlanta sits atop a ridge south of the Chattahoochee River. Atlanta has the highest average elevation of any major city east of Denver.

The Eastern Continental Divide line enters Atlanta from the south, proceeding to downtown. From downtown, the divide line runs eastward along DeKalb Avenue and the CSX rail lines through Decatur. Rainwater that falls on the south and east side runs eventually into the Atlantic Ocean while rainwater on the north and west side of the divide runs into the Gulf of Mexico via the Chattahoochee River. That river is part of the ACF River Basin, and from which Atlanta and many of its neighbors draw most of their water. Being at the far northwestern edge of the city, much of the river's natural habitat is still preserved, in part by the Chattahoochee River National Recreation Area. Downstream however, excessive water use during droughts and pollution during floods has been a source of contention and legal battles with neighboring states Alabama and Florida.

Atlanta has a humid subtropical climate, (Cfa) according to the Köppen classification, with hot, humid summers and mild, but occasionally chilly winters by the standards of the southern United States. July highs average 89 °F (32 °C) or above, and low average 71 °F (22 °C). Infrequently, temperatures can even exceed 100 °F (38 °C). The highest temperature recorded in the city is 105 °F (41 °C), reached in July, 1980. January is the coldest month, with an average high of 52 °F (11 °C), and low of 33 °F (1 °C). Generally average lows are in the upper 20s and lower 30s in the north Georgia region. Warm fronts can bring springlike temperatures in the 60s (high teens) and 70s (low 20s) in winter, and Arctic air masses can drop temperatures into the single digits (around -15 C) as well. The coldest temperature ever recorded was −9 °F (−23 °C) in February 1899. A close second was −8 °F (−22 °C), reached in January 1985. Atlanta's elevation keeps a more temperate climate than other southern cities of the same latitude due to its elevation being 1,050 feet (320 m) above sea level.

Like the rest of the southeastern U.S., Atlanta receives abundant rainfall, which is relatively evenly distributed throughout the year. Average annual rainfall is 50.2 inches (1,275 mm). An average year sees frost on 36 days; snowfall averages about 2 inches (5 cm) annually. The heaviest single storm brought 10 inches (25 cm) on January 23, 1940. Blizzards are rare but possible; one hit in March 1993. Frequent ice storms can cause more problems than snow; the most severe such storm may have occurred on January 7, 1973.
In 2007, the American Lung Association ranked Atlanta as having the 13th highest level of particle pollution in the United States The combination of pollution and pollen levels, and uninsured citizens caused the Asthma and Allergy Foundation of America to name Atlanta as the worst American city for asthma sufferers to live in.

On March 14, 2008, at approximately 21:40 Eastern Daylight Time, a category EF2 tornado hit downtown Atlanta with winds up to 135 mph (217 km/h). The tornado caused damage to Philips Arena, the Georgia Dome, Centennial Olympic Park, the CNN Center, and the Georgia World Congress Center. It also damaged the nearby neighborhoods of Vine City to the west and Cabbagetown, and Fulton Bag and Cotton Mills to the east. While there were dozens of injuries, only one fatality was reported. City officials warned it could take months to clear the devastation left by the tornado.

Atlanta's skyline is punctuated with highrise and midrise buildings of modern and postmodern vintage. Its tallest landmark – the Bank of America Plaza – is the 30th-tallest building in the world at 1,023 feet (312 m). It is also the tallest building in the United States outside of Chicago and New York City, and the tallest building in any state capital.
Midtown Atlanta

Unlike many other Southern cities such as Charleston, Savannah, and New Orleans, Atlanta chose not to retain its historic Old South architectural characteristics. Instead, Atlanta viewed itself as the leading city of a progressive "New South" and opted for expressive modern structures. Atlanta's skyline includes works by most major U.S. firms and some of the more prominent architects of the 20th century, including Michael Graves, Richard Meier, Renzo Piano, Pickard Chilton, and soon, Santiago Calatrava and David Chipperfield. Atlanta's most notable hometown architect may be John Portman whose creation of the atrium hotel beginning with the Hyatt Regency Atlanta (1967) made a significant mark on the hospitality sector. A graduate of Georgia Tech's College of Architecture, Portman's work reshaped downtown Atlanta with his designs for the Atlanta Merchandise Mart, Peachtree Center, the Westin Peachtree Plaza Hotel, and SunTrust Plaza. The city's highrises are clustered in three districts in the city — Downtown, Midtown, and Buckhead.[40] (there are two more major suburban clusters, Perimeter Center to the north and Cumberland/Vinings to the northwest). The central business district, clustered around the Hyatt Regency Atlanta hotel – one of the tallest buildings in Atlanta at the time of its completion in 1967 – also includes the newer 191 Peachtree Tower, Westin Peachtree Plaza, SunTrust Plaza, Georgia-Pacific Tower, and the buildings of Peachtree Center. Midtown Atlanta, farther north, developed rapidly after the completion of One Atlantic Center in 1987.

Tourism

Atlanta features the world's largest aquarium, the Georgia Aquarium, which officially opened to the public on November 23, 2005. The new World of Coca-Cola, opened adjacent to the Aquarium in May 2007, features the history of the world-famous soft drink brand and provides visitors the opportunity to taste different Coca-Cola products from around the world. Underground Atlanta, a historic shopping and entertainment complex lies under the streets of downtown Atlanta. Atlantic Station, a huge new urban renewal project on the northwestern edge of Midtown Atlanta, officially opened in October 2005.
The Varsity has been an Atlanta landmark for over 75 years.

Atlanta hosts a variety of museums on subjects ranging from history to fine arts, natural history, and beverages. Museums and attractions in the city include the Atlanta History Center; the Carter Center; the Martin Luther King, Jr. National Historic Site; the Atlanta Cyclorama and Civil War Museum; historic house museum Rhodes Hall; and the Margaret Mitchell House and Museum. Children's museums include The Fernbank Science Center and Imagine It! Children's Museum of Atlanta.

Piedmont Park hosts many of Atlanta's festivals and cultural events. Atlanta Botanical Garden sits next to the park. Zoo Atlanta, in Grant Park, features a panda exhibit. Just east of the city rises Stone Mountain, the largest piece of exposed granite in the world.

Colleges and universities

Atlanta has more than 30 institutions of higher education, including the Georgia Institute of Technology, a predominant engineering and research university that has been ranked in the top ten public universities since 1999 by US News and World Report, and Georgia State University. The city also hosts the Atlanta University Center, the largest consortium of historically Black colleges and universities in the country. Its members include Clark Atlanta University, Morehouse College, Spelman College, and the Interdenominational Theological Center. Adjoining the AUC schools, but independent from them, is the Morehouse School of Medicine. The Savannah College of Art and Design opened a Midtown Atlanta, campus in 2005 and shortly thereafter bought out and closed the Atlanta College of Art. Also in the city are the John Marshall Law School (Atlanta) and the Reformed Theological Seminary.

Suburban Atlanta contains several colleges, including Emory University, an internationally prominent liberal arts and research institution that has been consistently ranked as one of the top 20 schools in the United States by US News and World Report; Oglethorpe University, named for the founder of Georgia; Agnes Scott College, an all-women's college; and several state-run institutions such as Clayton State University, Georgia Perimeter College, Kennesaw State University, Southern Polytechnic State University, and the University of West.