Mill Hall, Pennsylvania

A water gap is a gap that flowing water has carved through a mountain range or mountain ridge and that still carries water today. Such gaps that no longer carry water currents are called wind gaps. Water gaps and wind gaps often offer a practical route for road and rail transport to cross the mountain barrier.

Bald Eagle Mountain – once known locally as Muncy Mountain – is a stratigraphic ridge in the Ridge-and-Valley Appalachians of central Pennsylvania, United States, running east of the Allegheny Front and northwest of Mount Nittany. It lies along the southeast side of Bald Eagle Creek and south of the West Branch Susquehanna River, and is the westernmost ridge in its section of the Ridge-and-Valley Appalachians. The ridge line separates the West Branch Susquehanna Valley from the Nippenose and White Deer Hole valleys, and Bald Eagle Valley from Nittany Valley.

U.S. Route 220 is a U.S. Highway that is a spur route of US 20. It runs from Rockingham, North Carolina, north to South Waverly, Pennsylvania. In the state of Pennsylvania, the route runs 248 miles (399 km) from the Maryland border in Cumberland Valley Township, Bedford County northeast to an interchange with Interstate 86 (I-86)/New York State Route 17 in South Waverly, Bradford County a short distance south of the New York border. Through the state, US 220 passes through the cities and towns of Bedford, Altoona, State College, Lock Haven, Williamsport, and Towanda. US 220 is concurrent with the entire completed Pennsylvania segment of I-99 between I-70/I-76 in Bedford and I-80 near Bellefonte. US 220 is also a freeway around Bedford, along the I-80 concurrency between Bellefonte and Mill Hall, between Mill Hall and Jersey Shore, from the western end of Williamsport to near Halls, and near the New York border. The remainder of US 220 in Pennsylvania is mostly a two-lane surface road.

Pennsylvania Route 64 is a 21.3-mile-long (34.3 km) north–south state route located in central Pennsylvania. At its southern terminus in Spring Township, PA 64 continues north from where Pennsylvania Route 26 turns to join Interstate 99 and U.S. Route 220. The northern terminus is at Pennsylvania Route 150 in Mill Hall. During its run, PA 64 carries the names Nittany Valley Drive and Water Street.

Pennsylvania Route 150 is a 41.1-mile-long (66.1 km) highway in Central Pennsylvania. Its southern terminus is at PA 26 in Dale Summit, Pennsylvania near State College, at the location of the Nittany Mall. Its northern terminus is at U.S. Route 220 in Avis.

Lock Haven is the county seat of Clinton County, in the U.S. state of Pennsylvania. Located near the confluence of the West Branch Susquehanna River and Bald Eagle Creek, it is the principal city of the Lock Haven Micropolitan Statistical Area, itself part of the Williamsport–Lock Haven combined statistical area. At the 2010 census, Lock Haven's population was 9,772.

Interstate 80 (I-80) in the US state of Pennsylvania runs for 311.12 miles (500.70 km) across the northern part of the state. It is designated as the Keystone Shortway and officially as the Z.H. Confair Memorial Highway. This route was built mainly along a completely new alignment, not paralleling any earlier US Routes, as a shortcut to the tolled Pennsylvania Turnpike to the south and New York State Thruway to the north. It does not serve any major cities in Pennsylvania and is mainly as a cross-state route on the Ohio–New York City corridor. Most of I-80's path across the state goes through hilly and mountainous terrain, while the route passes through relatively flat areas toward the western part of the state.

The United States Census Bureau (USCB), officially the Bureau of the Census, is a principal agency of the U.S. Federal Statistical System, responsible for producing data about the American people and economy. The Census Bureau is part of the U.S. Department of Commerce and its director is appointed by the President of the United States.

The United States census of 1850 was the seventh census of the United States. Conducted by the Census Office, it determined the resident population of the United States to be 23,191,876—an increase of 35.9 percent over the 17,069,453 persons enumerated during the 1840 census. The total population included 3,204,313 slaves.

The United States census of 1860 was the eighth census conducted in the United States starting June 1, 1860, and lasting five months. It determined the population of the United States to be 31,443,322 in 33 states and 10 organized territories. This was an increase of 35.4 percent over the 23,069,876 persons enumerated during the 1850 census. The total population included 3,953,762 slaves.

The United States census of 1870 was the ninth United States census. It was conducted by the Census Bureau from June 1, 1870, to August 23, 1871. The 1870 census was the first census to provide detailed information on the African American population, only five years after the culmination of the Civil War when slaves were granted freedom. The total population was 38,925,598 with a resident population of 38,558,371 individuals, a 22.6% increase from 1860.

The United States census of 1880 conducted by the Census Bureau during June 1880 was the tenth United States census. It was the first time that women were permitted to be enumerators. The Superintendent of the Census was Francis Amasa Walker. This was the first census in which a city—New York City—recorded a population of over one million.

The United States census of 1890 was taken beginning June 2, 1890, but most of the 1890 census materials were destroyed in 1921 when a building caught fire and in the subsequent disposal of the remaining damaged records. It determined the resident population of the United States to be 62,979,766—an increase of 25.5 percent over the 50,189,209 persons enumerated during the 1880 census. The data reported that the distribution of the population had resulted in the disappearance of the American frontier.

The United States census of 1900, conducted by the Census Office on June 1, 1900, determined the resident population of the United States to be 76,212,168, an increase of 21.01% from the 62,979,766 persons enumerated during the 1890 census.

The United States census of 1910, conducted by the Census Bureau on April 15, 1910, determined the resident population of the United States to be 92,228,496, an increase of 21 percent over the 76,212,168 persons enumerated during the 1900 census. The 1910 census switched from a portrait page orientation to a landscape orientation.

The United States census of 1920, conducted by the Census Bureau during one month from January 5, 1920, determined the resident population of the United States to be 106,021,537, an increase of 15.0 percent over the 92,228,496 persons enumerated during the 1910 census.

The United States census of 1930, conducted by the Census Bureau one month from April 1, 1930, determined the resident population of the United States to be 122,775,046, an increase of 13.7 percent over the 106,021,537 persons enumerated during the 1920 census.

The United States census of 1940, conducted by the Census Bureau, determined the resident population of the United States to be 132,164,569, an increase of 7.6 percent over the 1930 population of 122,775,046 people. The census date of record was April 1, 1940.

The United States census of 1950, conducted by the Census Bureau, determined the resident population of the United States to be 150,697,361, an increase of 14.5 percent over the 131,669,275 persons enumerated during the 1940 census.

The United States census of 1960, conducted by the Census Bureau, determined the resident population of the United States to be 179,323,175, an increase of 19 percent over the 151,325,798 persons enumerated during the 1950 census. This was the first census in which all states recorded a population of over 200,000. This census's data determined the electoral votes for the 1964 and 1968 presidential elections. This was also the last census in which New York was the most populous state.