MOCO Map of the Week--Average Household Size by Census Tract

MOCO Map of the Week is back after a short hiatus.  The next couple of maps will look at data on Households in Montgomery County.  Today's map shows the average household size by census tract using 2010 census data.*

The average household size in Montgomery County census tracts ranges from 1.3 to 3.99.  The average for the county as a whole is 2.7.  This is just slightly higher than the average household size for Maryland (2.6) and the DC metro area (2.64).

Two patterns stand out from the map below.  First, most tracts with high average household size are outside the beltway, in exurban areas in the county.  Second, tracts with low average household size tend to be located inside the beltway, or in between I-270 and Rockville Pike, where the majority of the county's multifamily housing is located. 

* Data are from the 2010 Census Summary File 1

MOCO Map of the Week--Percent White by Census Tract 2010

Today's map looks at the distribution of the white population in Montgomery county.  People who identify as white comprise 59% of the population in Montgomery County.  The white share of MOCO's population is slightly higher than it is for the state of Maryland (58.2%), but substantially lower than it is for the country as a whole (72.4%). 

Two patterns stand out from this map.  First, the white population in Montgomery is clustered in three places--along DC's western border (and extending along the Potomac), in the county's most western tracts, and in the northern tip of the county.  Second, there are four tracts where the white population is greater than 90%, and all of them are located inside the beltway in Friendship Heights/Bethesda (see mini-map below). 

MOCO Map of the Week--Ethnic Clustering Part 2

Today's map is a slight variation on my last map, which showed the spatial distribution of the county's Black/African American population.  Today's map is a standard deviation map.  This means that each tract is categorized based on where the Black/African American share of the population fits in the wider distribution (i.e. within one standard deviation of the mean, within two standard deviations, etc.).


A bit on measurement:  In the tracts outlined in black the Black/African American share of the population that is greater than 2 standard deviations from the mean share.  The mean share of the Black/African American population is 16.62%.  The standard deviation is 13.58%.  Tracts outlined in black have a Black/African American share of the population that is greater than 43.78% (i.e. the mean + 2 standard deviations).  

So, what are the notable patterns here?  Unlike the earlier standard deviation maps I produced for the Asian and Hispanic populations (you can see them here), there are not multiple clusters.  Instead, all of the tracts with a statistically significant share of the Black/African American population are near one another and located on the eastern edge of the county.  In many ways the eastern orientation is not surprising given that Blacks/African Americans comprise a majority of the population in neighboring Prince George's County.  

MOCO Map of the Week--Percent Black/African American by Census Tract, 2010

Today's map looks at the distribution of Montgomery County's Black/African American population by census tract.

People who identify as Black or African American comprise 16.62% of MOCO's population.  Their share in MOCO is lower than it is for the state (29.4%), but higher than it is in the country as a whole (12.6%).

A few spatial patterns stand out on today's map.  First, the Black/African American population is spatially clustered in two places in the county--Gaithersburg/Montgomery Village and along the border with Prince George's County.  Second, the top 5 census tracts with the highest percentages of Black/African American residents are all located on the eastern edge of the county (either bordering the county, or bordering a census tract that does). Finally, the county's Black/African American population is largely concentrated outside the beltway, despite a significant cluster along the northeastern border of DC.

Next map will look at statistically significant clusters of the Black/African American population.  Stay tuned! 

Map notes:  The data for this map is from the 2010 census.  The census does not disaggregate between people who identify as African American and those who identify as Black (usually, though not always people from other countries with African heritage).  

Map of the Week Bonus Edition--Ethnic Clustering

This is for all you map lovers out there!

The last two maps I've made showed that the distribution of two minority populations--Asian and Hispanic--in Montgomery County.  Today, I thought I'd take a look at the degree to which these two minority groups are clustered in a statistically significant way.

Stay with me statistics phobes.  There are pretty maps involved!

One way to see evidence of clustering is to create a standard deviation map.  This means that each tract is categorized based on where the minority share of the population in that tract fits in the wider distribution (i.e. within one standard deviation of the mean, within two standard deviations, etc.).

Evidence of statistically significant clustering would be found in tracts where the Asian or Hispanic share of a tract's population is more than two standard deviations from the mean.  

For both groups--Asians and Hispanics--there a 12 tracts with significant spatial clustering.  On the maps below these tracts are shaded in dark blue and outlined in black (as opposed to gray).  For the Asian distribution this means tracts where Asians comprise 29.4% or more of the total population.  The comparable figure for the Hispanic population is 42% or more.

Although both groups have significant clustering, the clustering tends to happen on different sides of the county--north and west for Asians and south and east for Hispanics.

What to make of all this?  Montgomery county may be exceptionally diverse, but that diversity isn't evenly across space.


Map 1: Asian Share of the Population, Classified by Standard Deviation

Map 2: Hispanic Share of the Population

MOCO Map of the Week--Percent Asian by Census Tract, 2010

This week's map shows the distribution of the Asian population in Montgomery County.  In 2010 13.9% of the county's population was Asian.

By comparison, only 5.52 % of Maryland's population was Asian in 2010.  For the US as a whole, the percent was even smaller, at 4.8%.

A couple of patterns stand out here.  First, Asians tend to be clustered outside the beltway, which runs in a straight line just above the District's northern tip (the top of the triangle at the bottom of the county).  Second, the census tracts with the highest percentages of Asians tend to be on the western side of the county. Next map will look at the distribution of the Hispanic/Latino population in MOCO.  Stay tuned!

MOCO Map of the Week--Median Age by Census Tract, 2010

MOCO Musings is introducing a new feature starting today--Map of the Week!  Today's map answers the question 'how old is Montgomery County?'  

The US Census Bureau reports that the county's median age in 2010 was 38.5 years.  This figure means we are slightly older than the US as a whole, which has a median age of 37.2.  There is, however, considerable variation when we look at median age by census tract.  The range across MOCO's 215 census tracts is substantial, ranging from 29.1 on the low end to 82.8 on the high end.  On the map below, the darker the tract, the higher the median age. 

The tract with the oldest median age (tract 703218) is located on the east side of Georgia Ave. just south of the Intercounty Connector.  Not surprisingly, a retirement community, Leisure World, takes us the majority of the tract.  The tract with the lowest median age (701422) is further east, along Columbia Pike, on the northside of the Intercounty Connector.   

Look for a map about once a week!

 

South Four Corners Makes it into the Washington Post!

This weekend my neighborhood made it into the Washington Post's 'where we live' column in the Real Estate section (http://www.washingtonpost.com/realestate/south-four-corners-is-at-the-intersection-of-suburbia-and-bustle/2014/02/13/ed51937a-7260-11e3-8def-a33011492df2_story.html).  I thought the author, Amy Reinink, did a great job capturing the flavor of my neighborhood, describing it as "at the intersection of suburbia and bustle."
 
But, being a geographer, I'm always thirsty for more spatial information.  So, I thought I'd share some census data for South Four Corners and compare it to the county as a whole.  Unfortunately, South Four Corners does not have its own census tract.  Rather, it is spread across two tracts, both of which include neighborhoods outside of the generally accepted borders of South Four Corners.

 The map on the left is from the Washington Post article linked above.  It shows the generally accepted boundaries of the neighborhood. The map on right side panel shows the census tracts in which South Four Corners is located (703.000 bordering the beltway and 703.100 just above it). Although these tracts include areas outside of South Four Corners, the neighborhood takes up a large share of both tracts.  So, we can still get a general sense of the neighborhood's demographics. 

























If we look at the racial background of three groups (white, Hispanic, and African American) from the 2010 census, South Four Corners differs in interesting ways from the county as a whole.  On the whole, South Four Corners is 'whiter' than the county.  Whites comprise 66% percent of the population across census tracts 703.000 and 703.100 while they take up a slightly smaller share of the county--63.2%.  Not surprisingly, minority populations take up a smaller share of the total population in South Four Corners as well.  However, there's one interesting caveat--the Hispanic share of the population is slightly higher in South Four Corners than it is in the county as a whole.  This may be due to the growth of the Hispanic population in the border area between Montgomery and Prince George's counties.

Share of the Population by race/ethnicity in South Four Corners and Montgomery County:

	MoCo as a whole	703.000	703.100	Avg of two census tracts
Percent White	63.2	72	60	66
Percent Hispanic	17.9	13	28	20.5
Percent African American or Black	18.3	11	13	12