Gov. Ralph Northam on Tuesday rolled out a $95 million plan to improve the quality and availability of early-childhood education to low-income families across Virginia, where more than 40 percent of children come to kindergarten unprepared.

The funding, part of the two-year budget plan that Northam (D) will unveil in full next week, would boost programs for 3- and 4-year-olds and represent “the largest single early childhood investment in our commonwealth’s history,” the governor said.

“We can emerge as a national leader and support our littlest learners,” said Northam, a pediatric neurologist. “When Virginia children thrive, all of Virginia thrives.”

Northam announced the plan at a Northern Virginia preschool with first lady Pam Northam, a former science teacher and pediatric occupational therapist. She has been visiting early education programs around the commonwealth this year — traveling 5,000 miles in all — to draw attention to the need for better quality and affordability.

The governor’s initiative would target “at-risk” children, meaning those who come from low-income homes or qualify for special education or both. Seventy-two percent of at-risk 3-year-olds and 24 percent of 4-year-olds lack access to quality care, Pam Northam said.

In all, the state has about 47,000 at-risk 4-year-olds and roughly the same number of at-risk 3-year-olds. As of the start of the current school year, about 35,000 of those 4-year-olds and 13,000 of the 3-year-olds were enrolled in quality early childhood programs.

Since then, about 6,500 children were taken off waiting lists as the state received federal grants covering low-income preschoolers as well as special-needs children up to age 12.

Under the governor’s budget plan, an additional 11,000 children would be enrolled over the next two years. That would still leave roughly 30,000 at-risk preschoolers on the waiting list for quality programs.

“Over two-thirds of parents are working outside the home now, and our families really struggle to find high-quality care and education opportunities for their children,” Pam Northam said. “Ralph and I with our backgrounds — pediatric neurologist, pediatric occupational therapist originally and then as an educator — saw firsthand every day in our practices how little brains grow exponentially in those first years and how critical that window of time is.”

The governor has begun previewing parts of the two-year state budget that he will formally present to legislators next week. On Monday, he announced a plan to spend nearly $22 million to reduce mortality rates during childbirth among women of color.

Democrats have pushed for years to expand preschool programs, but the Republican-controlled General Assembly warned that the expense would be too great. The odds for passage are better now for the General Assembly session that begins in January. In November, Democrats won control of both chambers in addition to the Executive Mansion. It will also help that the governor has made the plan part of his budget, said Del. Paul E. Krizek (D-Fairfax).

“If he has it in there, that makes all the difference,” Krizek said. “This will be a priority.”

Jeff Ryer, a spokesman for the Senate Republican Caucus, said members were waiting to see the whole budget plan before commenting.

A spokesman for House Republicans did not immediately respond to a request for comment.

Recently ranked the nation’s best state for business, Virginia falls in the bottom third when it comes to investment in early-childhood education, the governor’s office said. Northam’s proposal would apply to any preschool or child-care programs that accept public funds, including home-based and religiously affiliated schools.

They would be required to participate in a classroom assessment program to measure and improve the quality of instruction. The assessments, which some preschool programs have already undergone as part of a pilot program, were developed by the University of Virginia. They involve classroom observations and professional development for teachers.

Part of the plan calls for transferring oversight for child care and early education from the Department of Social Services to the Department of Education. That would streamline the “crazy quilt” of governance now in place across multiple state agencies, the first lady said.

The governor’s plan also includes $8 million for an incentive program to attract, train and retain early childhood teachers.

The first lady made a series of visits Monday and Tuesday to preschools and child-care centers in Northern Virginia. Those included an early education program at Warrenton United Methodist Church, which does not accept public funds but chose to participate in the assessment program to boost its quality.

The first lady also gave a preview of the plan at the Virginia Education Summit, a joint meeting of the state House and Senate education committees at George Mason University. In a panel discussion there, Jenna Conway — the state’s first chief school readiness officer, a position created under Northam — told the group that academically, “kids that look the worst are kids who report no preschool. . . . It is nearly impossible to catch those kids up.”

Tuesday’s announcement drew House Democrats from as far as southwest Virginia to ACCA Child Development Center in Annandale, including House Speaker-Designee Eileen Filler-Corn (D-Fairfax). Children there wished the crowd good morning in English, Arabic, Chinese, Japanese and Spanish.

Ninety percent of the students come from low-income families, yet the center has achieved the highest early-learning accreditation, Pam Northam said.

“Access and quality do not have to be mutually exclusive,” Pam Northam said.