An aerial view of the Riverdale Center 4 in 2002. - , Utah
July 2002
Riverdale Plaza 4
(Mann Fourplex)

4109 Riverdale Road
Riverdale, Utah 84405

(January 1978 to 1979 - Probably 2000)

Mann Theatres began a national expansion program in 1976 which would give in 75 new theaters by the end of the year.[1]  Between 1976 and 1982, the theater chain opened eight new theater complexes in Utah and converted one single-screen theater into a fourplex.

The Mann Riverdale Plaza 4 opened sometime between 31 December 1977 and 9 February 1979.[2][3]
In October 1979, Riverdale Theatre Corp, which operated the Riverdale Drive-In, filed suit against Mann Theatres for "parasitical misappropriation" in using "names which are deceptively similar" by naming its new four-theater complex the Riverdale Plaza Theaters.[4]  An advertisement for the theater in 1981 used the name "Mann Fourplex."[3]
The Riverdale Plaza Theaters most likely closed after Carmike Cinemas filed for Chapter 11 bankruptcy in August 2000.  Carmike was one of several theater chains which took on too much debt building new multiplexes with stadium seating and digital sound without closing enough older, underperforming theaters.[5]

1. "Mall Theater Expansion Planned", Salt Lake Tribune, 31 October 1976, page 2K
2. Advertisements in the Ogden Standard Examiner and the Signpost
3. "Advertisements", Riverdale Plaza 4 (Riverdale)
4. "Utah Briefs", Daily Herald, 11 October 1979, page 47
5. "Carmike closing doors on two local theaters", Daily Herald, 18 August 2000, page A5