PETALUMA, Calif. — On Sabbath morning, as fog still hung over the valley, the campers walked past the Torrey pines and blackberry bushes toward the garden. There, several rows of chairs had been arranged in front of an altar fashioned from a folding table covered with Senegalese cloth and a Torah scroll on loan from an Orthodox synagogue.

About 15 minutes into the service, two girls rose to lead the congregation in a series of prayers. “Baruch atah Adonai eloheinu, melech ha-olam, she’asani Yisrael,” they said. Then they switched to the English translation: “Blessed are You, Adonai our God, Sovereign of the Universe, who has made me a Jew.”

In all its ordinariness, as a standard part of liturgy, the assertion could hardly have been bolder, coming as it did from Amalia Cymrot-Wu and her camp buddy Maya Campbell. Maya is the daughter of an interracial black-white marriage, Amalia the product of Brazilian and Chinese bloodlines, and they were matter-of-factly proclaiming their place among the Jewish people.

Such is the mission of Camp Be’chol Lashon (“In Every Tongue”) here in the hills of Marin County about 35 miles north of San Francisco. For the past two years, it has provided the commonplaces of Jewish summer camp, right down to poison oak and bug juice, to an emerging population of Jews of color.

“If there’s Christians of all colors and all kinds, and Muslims of all colors and all kinds,” Amalia, 11, said over Shabbat lunch, “then why would Jewishness be any different?”

One of her fellow campers, Josh Rowen-Keran, 14, who was born to black and Korean parents and then adopted by an interracial couple in the Bay Area, sounded similarly nonchalant. “Being Jewish isn’t looking a certain way,” he said. “I could look at anyone and not know if they are or aren’t Jewish. You can’t know till you know the person.”

Yet what strikes these children as the same old same old, an American-Jewish community of multiple hues and heritages, has arrived as a seismic change. Religiously and historically, Judaism has generally placed little emphasis on evangelism and conversion.

While Israel’s law granting instant citizenship to any Jew has brought it a sizable number of Ethiopians and Indians, the American Jewish picture has looked much whiter. As the largest group of Jewish immigrants to the United States, those from Eastern Europe have set the cultural tone since the early 1900s. Their folkways — bagels, Yiddish, New Deal politics, Borsht Belt jokes — became a virtual religion. Which meant that nobody from outside could ever get completely inside.

Entering the new century, however, the demographers Gary and Diane Tobin conducted a survey that estimated that about 10 percent of America’s six million Jews were nonwhite. Their route into the community had been through conversion, adoption and interracial parentage, rather than Ellis Island. (Other scholars place the number of nonwhite Jews slightly lower, at roughly 450,000.)

Living out the phenomenon themselves, the Tobins adopted their African-American son, Jonah, soon after his birth 14 years ago. Between their continuing research and their parental experience, the Tobins began to worry about how much these Jews of color would ever be accepted and included.

“It was a sense of the Other, and we as a community are not great at dealing with the Other,” Ms. Tobin said. “We had centuries of persecution making us wary. We have a tendency to be more suspicious than welcoming.”

For a decade until Gary Tobin’s death in 2009, the couple ran a speakers’ series on Jewish diversity, arranged parties for Hanukkah and Shavuot, then held retreats for multiracial Jewish families at an outdoor education center here. All those efforts led to the opening of Camp Be’chol Lashon last summer with about 18 children, ages 8 to 16, from the Bay Area.

This year, the number has grown to 25, and word of mouth has brought campers from as far as Arizona and New Jersey. Some attend Jewish day schools and have had bar or bat mitzvah ceremonies; others have experienced little Jewish observance at home. For $1,800 apiece, they all get two weeks of participating in Jewish camping in both familiar and radically new ways.

They make challah covers, sometimes from Ghanaian kente cloth or Indian fabric. They hold a scavenger hunt called “Where in the world is Eliyahu?” — meaning the prophet Elijah — and earn clues by correctly answering questions about Jews around the world. (Q: A recording of religious music performed by Jews from which country won a Grammy Award? A: Uganda.)

The head counselor, Kenny Kahn, is a biracial Jew who attended the family retreats as a teenager. When the campers recited the Kaddish prayer for the dead during Sabbath worship, a boy named Adin said he was doing it in memory of his grandfather Oppenheimer and Martin Luther King Jr.

For all that is innovative at Be’chol Lashon, the socializing mission of the camp remains consistent with the goals of Jewish camps that have been operated for decades by the various religious movements, Zionist factions and cultural organizations.

“Camps transmit Jewish life effectively because they create a unified existence of friendship, independence and positive adult relationships in Jewish space, a calendar built on Jewish time such as Shabbat, and Jewish content,” said Riv-Ellen Prell, a professor of American Studies at the University of Minnesota, who has studied Jewish camping. “These camps succeed because they effectively create a sense of the importance of Jewish life and learning through performance, creativity and physical activity.”

So, during the Sabbath service, Rabbi Ruth Abusch-Magder guided the children through the Torah portion. The passage described the Jews near the Promised Land, and the 10 spies Moses sent to report on it, and the way all but two of them, Joshua and Caleb, returned with fearful reports.

“We remember the people who saw the good things,” the rabbi said. “That’s the challenge we have, to see the good things around us.”

As one girl listened, a butterfly landed on her pinkie. It just sat there, occasionally beating its beautiful wings, as other campers watched. One of them named it Eliyahu.