They arrived by foot and taxi, Metro and minivan, tens of thousands of Ethio­pian Americans gathering beneath the Washington Monument, some waving their country’s flag, others dressed in the traditional gauzy-white clothing of their homeland. Tourists wandered by and wondered what was happening. World Cup? Political demonstration?

Not this time.

In what organizers called one of the region’s largest gatherings of Ethiopians, thousands of people came from Virginia, Maryland, the District and several other East Coast areas Sunday evening to celebrate a holiday that falls on Sept. 11: the Ethio­pian New Year.

“Happy 2005!” Asratie Asfaw Teferra, 49, said proudly — the ancient African calendar still used in Ethi­o­pia being seven to eight years behind the Gregorian calendar. In addition to the new year, the festival commemorates the end of the country’s long rainy season, when the sun comes out and the fields fill with yellow daisies.

In the United States, there is neither a rainy season nor flower-filled fields — and Tuesday’s date has inauspicious connotations. But that hasn’t quelled the desire of Ethio­pian Americans to be embraced by their adopted land. They want to be an ethnic group that matters. They want to belong. And that means they want a holiday.

“We envision it like Cinco de Mayo, St. Patrick’s Day and the Chinese New Year,” said Teferra as he helped unload a station wagon filled with injera, the staple bread of Ethiopia. “Maybe in the past we were an insular culture. But now we run businesses and restaurants, we vote, we’re citizens. We’re part of the cultural tapestry of America.”

The new-year celebration is the latest and most prominent event in an effort to raise the political and economic profile of Ethio­pian Americans in the D.C. area.The organizers hope to stage an annual Ethio­pian New Year celebration at the Monument along with events like Saturday’s Ethio­pian Expo at the Capital Hilton, which is designed to promote Ethio­pian businesses in the country.

Having an Ethio­pian New Year in the United States could boost Ethio­pian businesses ­in the same way that St. Patrick’s Day does for Irish American businesses and could help raise funds for development projects in Ethi­o­pia, some say.

On Sunday, American and Ethio­pian flags were unfurled. Traditional Ethio­pian music filled the cool evening air on the Mall. Vendors sold “I Love Ethi­o­pia” baseball hats and English-language children’s books explaining Ethio­pian holidays; one computer company demonstrated “the world’s first Amharic computer keyboard,” referring to the country’s official language. And beneath the Monument, thousands waved yellow, green and red glow sticks — the colors of the Ethio­pian flag.

There was a prayer service for peace in their home country after the death last month of longtime ruler Meles Zenawi.

Teferra, dressed in a T-shirt made for the Ethiopian New Year, raced around the site talking to U.S. Park Police personnel and ensuring that the speaker systems worked. He works in international trade and lives in Hyattsville with his wife and their five children, all adopted from Ethiopia. He also runs the nonprofit Books for Africa, which seeks to end “the book famine on the continent.” His friends call him “Washington’s busiest Ethio­pian American.”

But tonight, he’s focused on turning the Ethiopian New Year into a popular American holiday. He has joined up with an eclectic group of leaders from the Ethio­pian diaspora: Ellias Fullmore, a dreadlocked half-Ethio­pian, half-African American ­hip-hop artist and video-game creator; Alemayehu Haile, a soft-spoken D.C. mental health counselor; and Anteneh Demelash, a gregarious banker. They call themselves the Ethiopian African 2000 Millennium Group, and together they raised $50,000 to stage the event, whose sponsors include Ethiopian Airways and Western Union, both visceral connections to the old country.

Washington is the perfect headquarters for the effort to make the Ethiopian New Year an annual event, the organizers say, because the Ethiopian population in the region has grown to 200,000 and the area is home to more African expatriates than any other place in the country, according to 2010 Census data.

A time-consuming calling

One night last week, Demelash, Teferra and other members of the Millennium Group crowded around a table for a strategy session at the Etete restaurant in the District’s Little Ethiopia.

Hosting the event at the Monument means that the group must have dozens of meetings with the National Park Service, which has to approve every detail. This entails, for instance, explaining the importance of serving Ethiopian honey wine because of its cultural significance as a celebratory new-year drink.

“At the Cherry Blossom festival, the Japanese got to serve their beer,” says Demelash, his eyebrows raised. “We did our homework. We know.”

They write letters to parks officials about the necessity of, say, lighting bamboo torches — or chibos — in a high-security area.

“Lighting chibo is critical for the holiday,” Teferra says. “Because it symbolizes the passing of seasons from darkness to light. People in the villages do this and sing afterwards, lighting up the countryside.”

All the explaining is a source of pride rather than irritation because securing the Monument is the key to making this holiday work, they say.

“It’s this assertion of our Ethiopian-American-ness, how much we respect our adopted country,” Teferra says.

“Did anyone get the letter from Obama’s people?” Fullmore calls out. At 34, he’s the youngest in the group. Because Fullmore understands both cultures, he serves as the group’s de facto liaison, simplifying cultural rituals and explaining the Ethio­pian New Year to organizations like President Obama’s campaign.

“We got the Obama message to be read at the Washington Monument! And his campaign even put in Happy New Year — ‘Melkam Enkutatash’ in Amharic,” Demelash cheers. “We knew Obama sent a similar message to the Persians in Virginia during their New Year! We deserve that recognition, too.”

Demelash ­has his laptop open, and he’s fielding cellphone calls from Ethio­pian American DJ Mamush about the event’s playlist and sound system.

“It’s like an obsession, a calling,” Demelash smiles, adding that he’s so dedicated to making the Ethiopian New Year an American holiday that he handed Oprah Winfrey a flier about the holiday when she was walking out of Howard University in 2007 after getting an honorary degree.

“Even my father thinks I work too much on it.”

A few hitches, but a good turnout

During the New Year, Ethiopians around the world attend prayer services, visit with family, exchange gifts and host colorful processions. Village children go door-to-door handing out fresh flowers to neighbors.

But at the foot of the Monument on Sunday, Ethio­pian Americans gathered with their children, who played soccer, ran on the nation’s lawn and danced to music by traditional Ethio­pian performers. Many American parents who adopted from Ethi­o­pia brought their children for a dose of their home country’s culture.

Because this is America, there was lots of stuff for sale. Because this is Washington, there were voter-registration booths and a campaign station run by African Americans for Obama.

­ And because launching a new holiday can be a tricky business, there were a few hitches. Saturday’s rainstorm delayed the setup, a triathlon blocked traffic for several hours and a health inspector from the National Park Service turned away some of the food — meats and Ethio­pian stews — because it didn’t meet Park Service requirements. Using a special thermometer, he found that the food was just a few degrees too hot. Caterer Askale Shiferaw, who had been cooking for two days, burst into tears. But in the end, she was allowed to bring in two trays of lentils and greens that were the right temperature.

“It’s all part of hosting an event this size at the Washington Monument. But it’s worth it. We want to be a part of American culture,” said Mackie Paulos, 35, wearing an “I love injera” T-shirt. She came from Ethiopia in 1995 and lives in Falls Church.

“The Ethio­pian New Year is a great holiday. It can work. It has to work.”