The women’s champion of the 2017 New York City Marathon, Flanagan these days coaches Nike’s Bowerman Track Club in Portland, Ore. But she saw an opportunity in the closely packed schedule created by the coronavirus pandemic, which pushed three spring races into the fall. She decided to run in all six major marathons, and to try to complete each one in under three hours — roughly a pace of under 6 minutes 50 seconds per mile.

After finishing the Chicago Marathon Sunday in 2:46:39 — and winning the women’s 40-44 division — she is halfway there.

Now comes the hard part.

Flanagan, who grew up in Marblehead, Mass., hopped on a plane to Boston on Sunday afternoon and will be on the starting line of her hometown marathon Monday morning in Hopkinton.

“It’s so typical of Boston to be the super hard part,” Flanagan said during an interview last week.

If she can walk after this weekend, she will do a virtual version of the Tokyo Marathon at home in Oregon in a week. Then it’s off to the New York City Marathon on Nov. 7.

That’s a heavy workload after two major knee reconstructions in 2019. Her patellas have hamstring tendons from cadavers.

“I missed pushing myself,” Flanagan, 40, said of life after the end of her competitive running career. “It was just fun to have a big goal again.”

“We all reach a point where we know we can’t make that podium anymore, but it’s difficult at that point to just walk away and not challenge yourself anymore,” said Kara Goucher, the former Olympian who has been competing in very long trail races the past few years.

Flanagan tried to mimic a shorter version of the Chicago-Boston double last month, running 20-plus miles on a flat course one day, then 21 miles at a 6:40-per-mile pace on hilly terrain the next day. Changing her 17-month-old son’s diapers and working in her garden after the first run served as a stand-in for the hectic journey from Chicago to Boston.

“I know I am a better person if I run,” she said. “I just needed something else other than running for the sake of running.”

In 2014, Meb Keflezighi of the United States won an emotional race one year after the 2013 bombing at the finish line. In 2018, Des Linden, another American, and Yuki Kawauchi of Japan prevailed during a freezing Nor’easter that made the race more a test of will than of speed.

A marathon that takes place during a pandemic probably qualifies as a unique circumstance, given the limitations on travel and the packed marathon schedule this fall that has spread the top talent among five major races. Still, there are several talented runners from East Africa who will be tough to beat: Lelisa Desisa of Ethiopia and Benson Kipruto of Kenya in the men’s race; Workenesh Edesa of Ethiopia and Angela Tanui of Kenya in the women’s.

That said, with temperatures expected to be in the 60s, this should not be a particularly fast race, unless there is a major tailwind. Linden, who this year became the first woman to break three hours for 50 kilometers, is in the field, and so is Scott Fauble, who lives and trains at altitude in Flagstaff, Ariz., and ran a 2:09 in Boston in 2019. Jordan Hasay, another fast American woman, has finished third twice and could be dangerous.

Rather than find another date for the marathon, as some activists demanded, the association apologized and offered to make the land acknowledgment. It also agreed to donate $20,000 to hold a celebration of Indigenous Peoples’ Day in Newton, one of the communities through which the marathon route passes. And it featured two Indigenous runners, Patti Dillon, of the Mi’kmaq, and Ellison Brown, of the Narragansett, on banners along the route.

The focus on Indigenous peoples added an unusual, somber note to marathon weekend, in the heart of a region that has long unreservedly celebrated its colonial history.

On Sunday night, two Navajo women performed a traditional Jingle Dress Dance at the finish line, tracing slow, bouncing circles in regalia strung with dangling metal cones, whose sound is believed to spread healing. Drums echoed in the canyon of Boylston Street.

One of the dancers, Erin Tapahe, 25, said she was running in part to bring attention to missing and murdered Indigenous women across the country by running in a long, red skirt, something she also did during training.

Love Richardson, 52, was one of 12 members of the Nipmuc Nation who were present for the pre-dawn acknowledgment on Monday.

She grew up in the central Massachusetts city of Worcester in the 1980s, and recalled her mother abruptly picking her up from school as Columbus Day and Thanksgiving approached, “because she didn’t want me to see those paper cutouts of turkeys and headdresses.”

She described it as “traumatic” to have been taught one version of colonial history at school and another, much more painful version at home. “We were not mentioned, we were colonized, assimilated,” she said.

Larry Spotted Crow Mann, 54, a Nipmuc singer and drummer, described Monday’s land acknowledgment as “amazing, kind of ineffable to describe,” despite the darkness and the bustle of marathon staff and the moving of trucks and cameras and equipment.

As soon as he started singing, he said, all of that seemed to disappear.

“I hope this is just the beginning of more press, and more coverage, in terms of doing it when it is actually light out,” said Mr. Mann, director of the Ohketeau Cultural Center in Ashfield, Mass. “Still, being there on that spot will leave an indelible mark.”

Galvez took an Uber back to his house, got into his truck and drove through the night. He left Chicago at 8:30 p.m. Central time on Saturday and arrived at about 1:45 p.m. Eastern on Sunday, stopping only for gas and water. “I made it here,” said Galvez, a construction worker who is running in his 10th Boston Marathon, which he calls the Super Bowl of marathons. “Next is to finish.”

Across social media, too, runners tweeted at airlines including Delta and Southwest, sharing stories of flights terminated just as boarding began, delays that led to missed connections, struggles to connect with agents to rebook flights and cancellations that meant spending hundreds of extra dollars to make it in time for Monday’s start.

By Sunday night, Southwest Airlines had canceled more than 1,000 flights or nearly 30 percent of its schedule, according to a FlightAware tracker. The airline blamed air traffic control issues and disruptive weather, but federal regulators attributed the disruptions to aircraft and staffing issues.

Tammy Conquest picked up her bib on Sunday afternoon, relieved to have her kit safely in hand. Conquest was traveling from Washington, D.C., and also encountered delays at the airport. But some of her running partners from Washington and other racers have not been as lucky. “I have friends who are stranded trying to get to Boston,” said Conquest, who works for the government. Their flights were canceled, then their Amtrak trains faced lengthy delays, she said.

“It’s my third marathon, but it feels like my first,” Conquest said, adding that the backdrop of the pandemic added to her race-day nerves.

Some 33,000 runners started and finished the race in Grant Park under humid conditions, with temperatures reaching well into the 70s. Ruth Chepngetich of Kenya was on pace to break the world record before settling for a dominant win, finishing in 2 hours 22:31 minutes. Seifi Tura of Ethiopia won the men’s race in 2 hours 06:12 minutes. Both are solid times given the uncomfortable conditions.

It was also a fairly impressive day for the Americans. Emma Bates and Sara Hall finished in second and third place among the women, and Galen Rupp finished second among the men.

As is often the case in big city races, though, much of the attention fell to the more than 30,000 participants and the tens of thousands of people who watched them, giving the country a glimpse of what things used to look like.

Chepngetich clearly has a talent for winning in warmer weather. She won the marathon at the world championships in Doha in 2019. That race had to be run at night to avoid the most severe temperatures, but still only 40 of the 68 runners finished the race in the 90-degree heat.

Boston should provide a little more comfort Monday, although temperatures will be in the high 60s and runners will be headed into a 10 mile-per-hour wind from the northeast.

Indeed, Massachusetts has one of the highest vaccination rates in the country, with 78 percent of residents over age 12 fully vaccinated.

The organizers had plenty of company. The two other major spring marathons, in Tokyo and London, also shifted to the fall. Organizers in Tokyo recently postponed the in-person version of their race again, but all the shifting created a glut of major marathons in the fall.

For their part, the Red Sox are scheduled to play at night — against the Tampa Bay Rays in their American League division series — rather than starting at 11 a.m. as they usually do on Patriots’ Day. Sadly, that means no Sam Adams party at Fenway for runners after the race.

The race was oversubscribed by more than 9,200 qualifiers, and with the field reduced by roughly one-third, runners had to beat the qualifying standard for their age group by 7 minutes 47 seconds to get into the race, since Boston accepts runners from fastest to slowest. That’s nearly three minutes faster than the previous record for the cutoff.

Instead of starting runners in multiple waves, organizers have set up a rolling start for everyone not in an elite competitive division. There will be no waiting around for hours at Hopkinton High School. It’s get off the bus and start running when you’re ready.

Runners need to be vaccinated or test negative for the coronavirus within 72 hours of the race. No one has to run with a mask, but runners have to wear them on the bus to the starting line and when they finish.

The biggest difference this year may be what unfolds on the sidelines. For the Boston region, the Patriots’ Day version of the marathon in April is usually a 26-mile party on a day when Massachusetts gives itself a hall pass from regular life.

There’s a lot of beer and plenty of barbecues on the lawns and sidewalks beside the racecourse, especially in the last 10 miles. Will those gatherings be as big and loud and boisterous during a pandemic as they were before it? If they are, at least a lot of them will be outside.

Now comes the oldest and grandest marathon of all: Boston, which until the pandemic had been run in April of every year since 1897. Organizers last year first postponed the race to the fall, then canceled the in-person event altogether for the first time in its 124-year history.

Monday’s version will be smaller, and have some different details, but once more Boston is set to hold a 26.2-mile celebration of running and itself like no other city does, beginning early Monday morning and running right into the start of the Red Sox playoff game at a packed Fenway Park, a little more than a mile from the finish line, Monday night.

It doesn’t get much more Boston than that. For one day at least, and especially for 20,000 marathoners, life might actually feel almost normal.

NBC Sports’s Paul Swangard will be calling the race, with additional analysis from the two-time Olympian Kara Goucher and the seven-time Paralympian Chris Waddell.

WBZ-TV, a local CBS station, will also carry the race beginning at 7 a.m. Eastern on Monday, featuring news and athlete interviews.

For those who miss the earlier coverage, the Boston Marathon will be rebroadcast on myTV38 in Boston and on NBC’s Olympic Channel at 8 p.m. on Monday night.