Hinggan Ling, Da, or Great Khingan, mountain range, Inner Mongolian Autonomous Region, NE China, extending c.750 mi (1,210 km) from the Amur River south to the Liao River; the highest point is 5,657 ft (1,724 m). The range forms the eastern edge of the Mongolian Plateau. Heavily forested, it has some of China's richest timber resources. The Xiao Hinggan Ling (Lesser Khingan), Heilongjiang prov., is a continuation of the Bureya range in Siberian Russia. It extends c.400 mi (640 km) NE from the Songhua River and is linked to the Da Hinggan by the Yilehuli (Ilkuri) range, N Heilongjiang prov.

Da may refer to:

• Da (play), a Tony-winning play by Hugh Leonard
• Da (film), a movie adaptation of the play by Hugh Leonard
• Dalton (unit), the atomic mass unit
• Adi Da, a spiritual leader once known as Da Free John, and Da Love-Ananda
• Da River in Vietnam
• SJ Da, a Swedish locomotive
• Deca-, an SI prefix for a factor of 10
• Da!, a Russian youth movement

DA or D.A. is an acronym or abbreviation for:

• DA postal area
• Daniel Amos, the American Rock band
• Danish language (ISO 639-1 alpha-2, da)
• Dark Ages (computer game)
• Darmstadt, a town in middle Germany
• Debtors Anonymous
• Deerfield Academy, a preparatory boarding school located in Deerfield, Massachusetts.
• Delt Ansvarlig Selskap, or DA, a Norwegian company form
• Democratic Alliance (South Africa), a South African political party.
• Department of Agriculture, an executive department in the Philippines.
• Deutsche Alternative (German Alternative), a rightist group
• DeviantArt, an online artistic community
• Diploma in Anaesthetics, an obsolete postgraduate qualification in anaesthetic practice
• DirectAdmin, a graphical web-based management utility
• District attorney (D.A.), a United States Attorney or County attorney
• The D.A. (1971 TV series), an NBC dramatic series
• The D.A. (2004 TV series), an ABC dramatic series
• Doctor of Arts degree
• Dopamine transmitter
• Doomsday argument
• Double anal A sexual act
• Dumbledore's Army in Harry Potter and the Order of the Phoenix
• Degtyarev Aviation-mounted, a Soviet machine gun
• Dura-Ace, a Shimano racing bicycle groupset
• Double action, a type of gun trigger
• Durham Academy, a private school
• Selskap med delt ansvar, a type of Norwegian company without limited liability
• Duck's Ass, a 1950's hairstyle