Beaumont finished on 208 on Saturday, the last batter to fall with England all out for 463 after tea on day three in reply to Australia’s 473.
Beaumont’s innings rewrote the record books, eclipsing Betty Snowball’s 189 scored against New Zealand in 1935 as the highest international score by an Englishwoman.
The knock was also the fifth highest of all-time in women’s Test cricket, and the third best in Ashes cricket behind Ellyse Perry’s 213 and Karen Rolton’s 209.
For periods on Saturday, it appeared as England were going to build a big lead, before Tahlia McGrath took three quick wickets and the hosts lost 4-15 late in their innings.
Ashleigh Gardner was Australia’s best with the ball, taking 4-99 and being the one to finally remove Beaumont after earlier claiming the key scalps of Heather Knight and Nat Sciver-Brunt.
But the day has belonged to the 32-year-old England opener.
Beaumont warmed up for the Ashes by posting 201 in a warm-up match against Australia A last week, and turned it on again in the Test match.
After offering several chances on Friday, and being incorrectly given not out when caught after a ball bounced off her bat and shoe, Beaumont was even more composed on Saturday.
Her only real chance came when she was given out lbw on 152 to Alana King, before ball-tracking showed a little over half the ball had pitched outside leg stump on review.
She hit 27 boundaries in her knock, flicking the quicks off her pads while also willing to be patient against the spin when Australia turned the screws either side of lunch.
The Sydney Thunder opener had previously combined in a 137-run third-wicket stand with Sciver-Brunt, who also offered up chances on Saturday morning before being removed by Gardner.
She struck three boundaries in row off Annabel Sutherland early in the day, hitting her through the legside twice and then guiding a ball behind point to the boundary.
Sciver-Brunt looked on for her second Test century, before Gardner speared a ball in and cramped the right-hander for room as she tried to play a cut shot.
Gardner also bowled Dunkley, when the No.5 charged down the wicket and tried to slog-sweep her, as she ended up with 4-99.