| Territorial Growth of the City of Pittsburgh | |||
| Territory Annexed | Entry Date | Area Annexed (Sq. Miles) | Total Area (Sq. Miles) |
| Borough of Pittsburgh | March 5, 1804 | 0.50 | 0.5 |
| City of Pittsburgh | March 18, 1816 | 0.5 | |
| Northern Liberties Borough | March 1, 1837 | 0.17 | 0.7 |
| City's District 8/17 | July 7, 1845 | 0.17 | 0.8 |
| Part of Pitt Township | November 4, 1846 | 0.8 | |
| Part of Pitt Township | December 4, 1846 | 0.93 | 1.8 |
| Part of Pitt Township | December 12, 1846 | 1.8 | |
| Remainder of Pitt Township | June 30, 1868 | 1.8 | |
| Peebles Township | June 30, 1868 | 1.8 | |
| Liberty Township | June 30, 1868 | 1.8 | |
| Collins Township | June 30, 1868 | 21.34 | 23.1 |
| Oakland Township | April 2, 1872 | 23.1 | |
| Lawrenceville Boro | April 2, 1872 | 23.1 | |
| Union Township | April 2, 1872 | 23.1 | |
| Temperanceville Boro | April 2, 1872 | 23.1 | |
| Mount Washington Boro | April 2, 1872 | 23.1 | |
| West Pittsburgh Boro | April 2, 1872 | 23.1 | |
| Monongahela Boro | April 2, 1872 | 23.1 | |
| South Pittsburgh Boro | April 2, 1872 | 4.19 | 27.3 |
| Allentown Boro | December 1, 1894 | 27.3 | |
| Birmingham Boro | December 1, 1894 | 27.3 | |
| East Birmingham Borough | December 1, 1894 | 27.3 | |
| St. Clair Borough | December 1, 1894 | 27.3 | |
| Brushton Boro | December 1, 1894 | 0.45 | 27.8 |
| Beltzhoover Boro | March 1, 1898 | 0.30 | 28.1 |
| Elliott Boro | January 2, 1905 | 0.32 | 28.4 |
| Esplen Boro | January 8, 1906 | 0.28 | 28.6 |
| Sterett Township | January 8, 1906 | 0.48 | 29.1 |
| Montooth Boro | January 7, 1907 | 0.11 | 29.2 |
| Sheraden Boro | November 21, 1907 | 0.97 | 30.2 |
| City of Allegheny | December 6, 1907 | 8.07 | 38.3 |
| West Liberty Boro | January 6, 1908 | 2.74 | 41.0 |
| O'Hata Township | October 30, 1908 | 0.32 | 41.3 |
| Beechview Boro | Januayr 4, 1909 | 0.33 | 41.7 |
| Part of Union Township | January 4, 1909 | 0.09 | 41.8 |
| Part of Baldwin Township | January 1, 1912 | 0.24 | 42.0 |
| Part of Ross Township | December 19, 1916 | 0.02 | 42.0 |
| Spring Garden Boro | January 5, 1920 | 0.19 | 42.2 |
| Part of Penn Township | June 28, 1920 | 0.00 | 42.2 |
| Part of Chartiers Township | October 4, 1920 | 0.02 | 42.2 |
| Rmeainder of Chartiers Township | January 1, 1921 | 3.42 | 45.7 |
| Part of Reserve Township | October 31, 1922 | 0.25 | 45.9 |
| St. Clair Boro | January 1, 1923 | 0.97 | 46.9 |
| Parts of Lower St. Clair Township | February 7, 1924 | 0.08 | 47.0 |
| Part of Swissvale Boro | November 27, 1925 | 0.03 | 47.0 |
| Carrick Boro | January 3, 1927 | 1.59 | 48.6 |
| Knoxville Boro | January 3, 1927 | 0.30 | 48.9 |
| Westwood Boro | January 3, 1927 | 0.30 | 49.2 |
| Union Township | January 2, 1928 | 0.94 | 50.1 |
| Part of Ross Township | June 29, 1928 | 0.06 | 50.2 |
| Hays | January 7, 1929 | 0.74 | 50.9 |
| Part of Mifflin Township | February 15, 1929 | 0.92 | 51.8 |
| Part of Ross Township | April 22, 1929 | 0.03 | 51.9 |
| Part of Ross Township | April 25, 1929 | 0.13 | 52.0 |
| Part of Ross Township | June 3, 1929 | 0.01 | 52.0 |
| Part of Ross Township | July 1, 1929 | 0.00 | 52.0 |
| Part of Mifflin Township | July 22, 1929 | 0.00 | 52.0 |
| Part of Penn Township | January 2, 1930 | 0.03 | 52.1 |
| Part of Penn Township | January 22, 1930 | 0.02 | 52.1 |
| Overbrook Boro | January 6, 1930 | 1.23 | 53.3 |
| Part of Baldwin Township | January 5, 1931 | 0.08 | 53.4 |
| Part of Mifflin Township | February 27, 1931 | 0.76 | 54.1 |
| Part of Reserve Township | March 20, 1931 | 0.15 | 54.3 |
| Part of Baldwin Township | December 1, 1947 | 0.06 | 54.4 |
| Part of Ross Township | April 28, 1948 | 0.02 | 54.4 |
| Part of Baldwin Township | February 5, 1951 | 1.08 | 55.5 |
| Part of Baldwin Township | March 13, 1951 | 0.04 | 55.5 |
| Part of Robinson Township | August 19, 1955 | 0.03 | 55.5 |
| Source: Office of the Pittsburgh City Controller | |||