By its own public count, the U.S. has 598 military facilities in 40 countries, along with the 4,461 bases in the U.S. and U.S. territories. http://theweek.com/article/index/257406/what-would-a-us-russia-war-look-like
You need to define facility and base. The Base Structure Report (BSR) lists real property assets. These so-called bases are buildings and other real property.
Display Criteria : To qualify for individual entry in the BSR, a DoD site located in the United States must be larger than 10 acres AND have a Plant Replacement Value (PRV) greater than $10 million. If the site is located in a foreign country, it must be large r t han 10 acres OR have a PRV greater than $10 million to be shown as a separate entry. Sites that do not meet these criteria are aggregated as an “Other” location within each state or country. Since Army National Guard State sites tend to be smaller, the c riteria were adjusted so that sites larger than five acres AND have a PRV greater than $5 million are shown. Army National Guard sites not meeting this criteria are aggregated as “Other” for each state.
"The DoD manages a worldwide real property portfolio that spans all 50 states, seven U.S. territories, and 40 foreign countrie s. The majority of the foreign sites are located in Germany (179 sites), Japan (109 sites), and South Korea (83 sites).