| Position: | Defence |
| Shoots: | Right |
| Height Ft: | 5 |
| Height In: | 11 |
| Weight Lb: | 190 |
| Played For: | Philadelphia Flyers Los Angeles Sharks Vancouver Blazers |
| Birth Date: | September 8, 1942 |
| Birth Place: | Hawkesbury, Ontario, Canada |
| Death Place: | Glengarry, Ontario, Canada |
| Career Start: | 1964 |
| Career End: | 1977 |
Donald Ralph "Big Mac" MacSweyn (September 8, 1942 – May 21, 1995) was a Canadian professional ice hockey defenceman. He played 47 games in the National Hockey League (NHL) with the Philadelphia Flyers from 1968 to 1972 and 147 games in the World Hockey Association (WHA) with the Los Angeles Sharks and Vancouver Blazers from 1972 to 1974. The rest of his career, which lasted from 1964 to 1978, was spent in the minor leagues.
A native of Laggan, Ontario, MacSweyn played for teams in the NHL, EHL, WHL, AHL, WHA, SHL, NAHL, SLSHL, and the OIHA.
MacSweyn was a member of the EHL North First All-Star Team in 1967, member of the AHL First All-Star Team in 1971, and a member of the AHL Second All-Star Team in 1972.
MacSweyn retired from playing hockey in 1977. After his retirement, MacSweyn returned to his family farm and also was involved in coaching his daughter's hockey team. In 1993 MacSweyn was inducted into the Glengarry Sports Hall of Fame in Glengarry, Ontario. On May 21, 1995, MacSweyn died in Glengarry, Ontario, at the age of 52. He was survived by his wife and two daughters.
| Regular season | Playoffs | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Season | Team | League | GP | PIM | GP | G | A | Pts | PIM | |||||
| 1964–65 | Johnstown Jets | EHL | 28 | 2 | 17 | 19 | 35 | 5 | 0 | 1 | 1 | 6 | ||
| 1965–66 | Johnstown Jets | EHL | 71 | 6 | 26 | 32 | 38 | 3 | 0 | 0 | 0 | 0 | ||
| 1966–67 | Johnstown Jets | EHL | 72 | 6 | 28 | 34 | 82 | 5 | 0 | 3 | 3 | 6 | ||
| 1966–67 | Portland Buckaroos | WHL | 1 | 0 | 0 | 0 | 0 | — | — | — | — | — | ||
| 1967–68 | Philadelphia Flyers | NHL | 4 | 0 | 0 | 0 | 0 | — | — | — | — | — | ||
| 1967–68 | Quebec Aces | AHL | 51 | 2 | 11 | 13 | 56 | 15 | 0 | 8 | 8 | 37 | ||
| 1968–69 | Philadelphia Flyers | NHL | 24 | 0 | 4 | 4 | 6 | 4 | 0 | 0 | 0 | 4 | ||
| 1968–69 | Quebec Aces | AHL | 41 | 1 | 12 | 13 | 30 | — | — | — | — | — | ||
| 1969–70 | Philadelphia Flyers | NHL | 17 | 0 | 0 | 0 | 4 | — | — | — | — | — | ||
| 1969–70 | Quebec Aces | AHL | 54 | 2 | 19 | 21 | 31 | 6 | 0 | 3 | 3 | 9 | ||
| 1970–71 | Quebec Aces | AHL | 72 | 2 | 24 | 26 | 50 | 1 | 0 | 0 | 0 | 2 | ||
| 1970–71 | Philadelphia Flyers | NHL | — | — | — | — | — | 4 | 0 | 0 | 0 | 2 | ||
| 1971–72 | Philadelphia Flyers | NHL | 2 | 0 | 1 | 1 | 0 | — | — | — | — | — | ||
| 1971–72 | Richmond Robins | AHL | 60 | 0 | 15 | 15 | 52 | — | — | — | — | — | ||
| 1972–73 | Los Angeles Sharks | WHA | 78 | 0 | 23 | 23 | 39 | 6 | 1 | 2 | 3 | 4 | ||
| 1973–74 | Los Angeles Sharks | WHA | 13 | 0 | 3 | 3 | 6 | — | — | — | — | — | ||
| 1973–74 | Vancouver Blazers | WHA | 56 | 2 | 18 | 20 | 52 | — | — | — | — | — | ||
| 1974–75 | Richmond Robins | AHL | 54 | 1 | 6 | 7 | 32 | 6 | 0 | 3 | 3 | 6 | ||
| 1975–76 | Baltimore Clippers | AHL | 74 | 4 | 8 | 12 | 42 | — | — | — | — | — | ||
| 1976–77 | Richmond Wildcats | SHL | 37 | 1 | 6 | 7 | 10 | — | — | — | — | — | ||
| 1976–77 | Johnstown Jets | NAHL | 26 | 0 | 7 | 7 | 10 | 3 | 0 | 2 | 2 | 0 | ||
| WHA totals | 147 | 2 | 44 | 46 | 97 | 6 | 1 | 2 | 3 | 4 | ||||
| NHL totals | 47 | 0 | 5 | 5 | 10 | 8 | 0 | 0 | 0 | 6 | ||||