The baby that set Washington buzzing Monday night, when D.C. Mayor Muriel E. Bowser (D) made a surprise announcement that she had adopted a child, is a girl named Miranda Elizabeth Bow­ser who was born last week, city officials said.

Bowser and her aides have declined to release basic information about the baby, leading some in the media to refer to the child generically as “Baby Bowser.”

However, a mayoral aide told a handful of D.C. officials about the baby as they gathered in Las Vegas on Monday night for a retail convention, according to city officials who were present. City Administrator Rashad M. Young announced the child’s name and gender and said she was born last week, the officials said. The baby’s initials match Bowser’s.

The mayor, 45, is the first single mother to run the city.

She told WUSA Channel 9 that it was the right time to start a family.

“I decided to start the adoption journey, just knowing that it was a great time in my life and I had so much to share with a baby,” she said in a brief interview that aired Monday night. “When you sit in the seat that I’m in, you’re used to being able to make things happen, and babies have a way of letting you know that they’re in control.”

While Bowser started the adoption process late last year, she said she learned that a placement was possible “much sooner than I expected,” and that she brought the infant to her Colonial Village home over the weekend.

She canceled a previously scheduled campaign rally and other appearances Saturday. A campaign spokesman said at the time that she was ill.

The baby arrives as Bowser is on track to become the first District mayor elected to a second term since 2002. She faces no serious competition in the June 19 Democratic primary or the general election.

Bowser, who has never married or had other children, is known for shielding her personal life from public view, and that tendency could be seen in her handling of the announcement that she was a new mom.

Unlike other elected officials with newborns — such as D.C. Council member Brianne K. ­Nadeau (D-Ward 1), who delivered a girl last year, or Sen. Tammy Duckworth (D-Ill.), who last month became the first ­sitting U.S. senator to give birth — Bow­ser opted not to make public even the simplest information about her new child.

She asked for privacy in a Monday evening statement.

“As any new mother would feel — I am thrilled, nervous and looking forward to each and every stage,” Bowser wrote in a tweet.

“Because of the great team we have, I don’t expect we’ll miss a beat, and I know we’ll all keep working hard to make D.C. proud,” she added.

Anu Rangappa, the mayor’s communications director, on Tuesday declined to answer questions about the circumstances of the baby’s adoption, the mayor’s child-care arrangements when she returns to work next week, whether a co-parent will help raise the baby and whether Bow­ser would reduce her schedule because of obligations as a single parent.

“That’s a great list!” Rangappa wrote in an email responding to The Washington Post’s questions. “We are allowing the mayor time to focus on the early stages of being a new mom.”

Newborns are typically adopted from within the United States either through an agency or a private adoption negotiated directly between the birth parent and adoptive parent, said Jennifer Fairfax, an adoption attorney based in Silver Spring, Md.

In either case, an adoptive parent would have to undergo a “home study” to assess parental fitness, examining such issues as their health and financial security. Fairfax said public figures often choose to adopt through an agency because the process of finding a birth parent is more confidential.

Bowser joins a small number of single parents holding public office, even though they make up about a quarter of U.S. families.

“When you see these women in positions of power do that, it really bodes well for other women who can look and say, ‘I can do that. If I have children, I can run for office. And even if I don’t, I can still have kids when I reach a certain position,’ ” said Andrea Steele, president of Emerge America, which recruits and trains women to run for office.

Child care in the District is extremely expensive compared with most U.S. cities, according to the Economic Policy Institute. The mayor said becoming a parent will give her a new perspective on the concerns of D.C. families.

“It certainly gives me another point of view. I have, we have been very focused on families in this administration, making sure that we do everything for schools and child care and great play spaces and safe neighborhoods,” Bowser told WUSA.

Bowser will not be the first D.C. mayor to have newborn children while in office: Marion Christopher Barry was born in 1980, two years after his father, Marion Barry, was elected to his first term. And Adrian Fenty’s third child was born halfway through his term in 2008.

Members of the D.C. Council who are also parents of young children offered their congratulations to Bowser. “Zoe can’t wait to meet her new friend,” Nadeau wrote on Twitter.

Here are some other reactions to the mayor’s news:

Aaron C. Davis and Perry Stein contributed to this report.