The good old days of the 1960s were good, especially for Pennsylvania’s population. The 1970 census revealed that Pennsylvania had a population increase of 4.2 percent in the 1960s.That’s almost 50 percent higher than the state’s population increase in the 2010s, as revealed recently. The state’s population grew by only 2.4 percent in the 2010s, far below the national average of 7.4 percent.The population increase in the 1960s was part of a growth spurt across the commonwealth. Back then, 44 counties saw population increases, with 23 seeing decreases.Twelve counties in the 1960s had population increases over 10 percent. According to the 2020 Census, only one county had an increase of over 10 percent. That was Cumberland County, located in Central Pennsylvania, with a growth rate of 11.2 percent.Leading the way in the 1960s was Bucks County, outside of Philadelphia, with a 34 percent increase. Here’s a list of the counties with the highest growth percentages in Pennsylvania in the 1960s.