It was one of four stages set up to host the weekend's 48-band lineup.
O'Connor said Lunar Bay was the first music festival of her "summer adventure," traveling the country and attending similar festivals.
"It's awesome," she said. "I love how beautiful [Steppingstone] is and how it's right next to the hills and the river."
Britton, Coakley and Duncan call themselves the "Ladies of Locust," after the Havre de Grace street they live on.
"We plan to be here for a long, long time... it's only going to get better and better," Duncan said.
Forty-one vendors of various arts and crafts were also scheduled to be available during the festival.
"We're about showcasing the beauty of Harford County and just generating money for the entire county," Coakley said.
Max Montague and Kiana Noorishad of Washington, D.C., and their Chihuahua, Snoop, relaxed on a blanket, taking in the music and the sunny weather.
Noorishad said the festival offered "very good food."
"We're big foodies and we like the music, so it's a good combination," she said.
Montague said he and Noorishad attend a "couple" of music festivals each summer; he called Lunar Bay's venue "a little more scenic and a little more intimate" than other festivals in the area.
He also liked that their canine companion could attend.
"We go to a fair amount of music festivals that are a little larger, and we've never been able to bring dogs before, so it's a nice plus," he said.
Harford County residents who attended Lunar Bay Saturday enjoyed having the festival close to home.
Chris Widomski of Fallston, who came with his wife, Shannon, and their sons, Charlie, 9, and Sammy, 7, recalled having to travel to Southern Maryland or West Virginia during the 1990s to see music festivals with jam bands.
"It took forever to get there and line was out the door," he said of shows in West Virginia.
Widomski said Lunar Bay was the first music festival for his sons, and said it was "absolutely" a good experience for children.
"It's always cool and there's no fighting, no crazy stuff happening," he said. "Everybody's on the same kind of wavelength."
Heather Ujvarosy of Bel Air followed her 2-year-old daughter, Zoe, closely as she explored the vendor area; Zoe was also taking in her first festival.
Ujvarosy said it was "a whole lot to take in for somebody her age," but noted her daughter had many things to occupy herself with.
"She has her bubbles and balloons, and people have been very sweet, giving her balls to play with, and more balloons," Ujvarosy said.
A portion of the Lunar Bay proceeds will benefit five local and regional nonprofits, including Believe in Music of Baltimore; The Arc, which has chapters throughout the state assisting people with developmental disabilities; Pets on Wheels, which transports dogs and cats to visit people in nursing homes, veterans' hospitals and other institutions; Steppingstone; and Murals of Grace, established through the Havre de Grace Main Street Organization's Arts & Entertainment Committee, to paint murals around the city.
"I think what they're doing for this community is very amazing and special, to bring this much talented music to this area," Kenny Liner, program director for Believe in Music, said of Lunar Bay's organizers.
The organization is a partner of the Living Classrooms Foundation of Baltimore, and provides music education to Baltimore youth.
Lunar Bay organizers are already planning ahead for next year.
Duncan said some minor adjustments may be made, such as adding a tent, but they hope to keep the event essentially the same.
"We are heading that way next year," she said, adding they hope to keep it "specialized," with interesting art and food.