According to NAHB estimates, the total count of second homes was 7.4 million, accounting for 5.6% of the total housing stock in 2016. This analysis focuses on the number and location of second homes qualified for the home mortgage interest deduction using the Census Bureau’s 2016 American Community Survey (ACS).

As of 2016, the state with the largest stock of second homes was Florida (1.1 million), accounting for 15% of all second homes. Half of the nation’s second homes can be found in eight states – Florida, California, New York, Texas, Michigan, North Carolina, Arizona, and Pennsylvania.
In-depth analysis of the county level data shows that the concentration of second homes is not simply restricted to conventional locations like beachfront areas. There were 916 counties spread over 49 states, where second homes accounted for at least 10% of the local housing stock. Only Connecticut and Washington D.C. were exceptions. 363 counties, 12% of all counties in the U.S., had at least 20% of housing units that were second homes.

In total, 33 counties in 13 states had over half of housing units qualified as second homes. Of these counties, five counties are in Michigan, four in Wisconsin, three in Colorado, two in Massachusetts and New Mexico, and one county each in California, Maryland, Minnesota, Missouri, New Jersey, Pennsylvania, Texas, and West Virginia. These national patterns are mapped below.

Of course, the geographic locations of second homes also correspond to population density. Counties with more than 25,000 second homes are mostly located in or near metropolitan areas. The table below lists the top 10 counties with the most second homes. States with at least one such county are Arizona, Florida, California, Massachusetts, Illinois, New York, New Jersey, Nevada, South Carolina, Delaware, Texas, Michigan, North Carolina, and Maryland.

NAHB estimates are based on the definition used for home mortgage interest deduction: a second home is a non-rental property that is not classified as taxpayer’s principal residence. Examples could be: (1) a home that used to be a primary residence due to a move or a period of simultaneous ownership of two homes due to a move; (2) a home under construction for which the eventual homeowner acts as the builder and obtains a construction loan (Treasury regulations permit up to 24 months of interest deductibility for such construction loans); or (3) a non-rental seasonal or vacation residence. However, homes under construction are not included in this analysis because the ACS does not collect data on units under construction.