The differences in the way the U.S. Censuses have counted people reflect the government’s perspectives on who is important to count. Groups of people counted within the broad categories of slave [historical category], race, ethnicity, or nationality are often hidden. 

For example, eighteenth and early nineteenth century census data recorded the numbers of enslaved peoples without acknowledging that they too were immigrants, as many were born in present day Sierra Leone, Ivory Coast, Liberia, Ghana, and the Caribbean. (For more information on this, see the page in this exhibit on Enslavement. The category Asian also obscures identity. For example, national-ethnic groups such as Chinese, Cambodian, and Vietnamese are not differentiated. Similarly, Latino, first used in 1970, conceals indigenous identities such as Mayan and national-ethnic  identities such as Mexican, Guatemalan, and Salvadoran. 

The county and the country were only 14 years old. The census recorded numbers of people in the following categories: Free white Males of 16 years and upwards, Free white Males under 16 years, Free white Females of all ages, All other free Persons, Slaves. The next five censuses (1800, 1810, 1820, 1830, 1840) collected similar information without differentiating those born in other countries.

The foreign born came from Ireland, Germany, England, and Canada. 

This was the first year that country of origin was included in the census data, mostly specifying nationalities from Europe. Most of the foreign born came from Ireland, Germany, England, and Wales and others came from British American colonies, Scotland, and France. One of the foreign born came from Norway or Sweden. 

Only about 1% of the county's population are foreign born, a drop from the previous decades. Most of the foreign born still come from Germany, Ireland, England, Scotland, and Canada; however, fourteen people came from Russia, five from China, and four from Italy and other countries. Notably, two people were born "at sea."

The foreign born came from, in order starting with the highest number: England,  Germany, Canada, Ireland, Scotland, Russia, Switzerland, France, Italy, Austria, Denmark, Sweden, Poland, Wales, Czechoslovakia, Netherlands, Norway, Hungary, and Romania. 

There is a notable increase in the diversity of nationalities recorded in this census. Most of the foreign born are still coming from England and Germany, but the numbers of Russians and Eastern Europeans increases and people from Mexico, Cuba, Central and South America, Palestine and Syria, and Asia are also recorded. 

By 1960 Montgomery County had the greatest number of foreign born in the state of Maryland. Most of the foreign born came from the USSR. Census data reflected the chaos and displacement of WWII that was missing from the 1950 reports. Twenty-five different nations of origin were listed.  Of note: Americans could choose their own racial category for this census.

"Hispanic Origin" was an option for the first time in the county, with four percent of the population listed under that category. Further divisions within it included "Mexican, Puerto Rican, Cuban, or Other." Categories represent races as well as certain ancestries and provide some measures of diversity. 

 The countries where the most foreign born came from include El Salvador, China, India, Korea, Vietnam, and Iran. Of note, Americans could choose more than one racial category for this census.