4,480 people are employed at Houghton Mifflin Harcourt.
Houghton Mifflin Harcourt is based in Boston, Massachusetts.
The NAICS codes for Houghton Mifflin Harcourt are [513, 51, 5111, 511, 51113, 511130].
The SIC codes for Houghton Mifflin Harcourt are [273, 27].