Collin County Back to School 2026: The Districts That Are Growing and the Ones That Are Not

Summer is moving fast, and back-to-school season in Collin County arrives earlier than many families expect. But the 2026-27 school year brings a story that goes beyond calendars and supply lists — a genuine split in the county between districts still growing fast and districts managing enrollment decline for the first time in their histories. Here are the verified first-day dates and everything parents need to know across every major Collin County school district. Verified First Day Dates 2026-27 Plano ISD: Tuesday, August 11, 2026 Prosper ISD: Tuesday, August 11, 2026 Frisco ISD: Wednesday, August 12, 2026 Celina ISD: Wednesday, August 12, 2026 McKinney ISD: Thursday, August 13, 2026 Allen ISD: Thursday, August 13, 2026 The Districts Still Growing Celina ISD — First Day August 12, 2026 Celina ISD is experiencing some of the most dramatic enrollment growth of any district in Texas. Enrollment surpassed 5,500 students in early 2025, and demographers project it could reach 13,000 by 2029-30 and climb past 23,000 by the mid-2030s — a trajectory that led voters to approve a $2.27 billion bond package in May 2025 to fund new campuses. Willard Middle School opens this fall to relieve overcrowding. Registration is ongoing at celinaisd.com. Prosper ISD — First Day August 11, 2026 Prosper ISD is one of the fastest-growing districts in Texas. Two new elementary schools open this fall to accommodate rapid enrollment growth. Families in newer Prosper neighborhoods should verify campus assignments before school begins, as boundaries shift regularly. Registration at prosperisd.org. McKinney ISD — First Day August 13, 2026 McKinney ISD serves approximately 23,300 students and continues to see steady growth. Teachers report back August 4 ahead of the August 13 start date. The board has set graduation for all three high schools on May 28, 2027, at the Credit Union of Texas Event Center in Allen. Full calendar at mckinneyisd.net. The Districts Managing Decline Frisco ISD — First Day August 12, 2026 Frisco ISD serves more than 60,000 students across dozens of campuses — down from a peak of roughly 67,000 in 2023. After growing by thousands of students a year for over a decade, the district is now managing enrollment decline for the first time in its history. A district official described it plainly: "we were the fastest growing school district in the country and the state for years and years and years, growing 3,000 students a year for 15 years" — past tense. Frisco ISD has even opened enrollment to non-resident students to fill empty seats. One scheduling note: Frisco ISD's calendar committee moved up the last day of school to May 14, 2027 — a week earlier than normal — to avoid conflicts with the PGA Championship, which is expected to draw roughly 30,000 visitors a day to Frisco that May. Supply lists and open house dates at friscoisd.org. Plano ISD — First Day August 11, 2026 Plano ISD, serving roughly 43,800 students in 2025-26, has seen enrollment fall by more than 2,600 students year-over-year — part of a longer decline from a 2012 peak of 55,659. The district closed four campuses in 2025 and is projecting a further drop to around 41,800 students for 2026-27, alongside a budget shortfall exceeding $40 million. Supply lists and open house information at pisd.edu. Allen ISD — First Day August 13, 2026 Allen ISD, long known for its academics and its Eagle Stadium, is now navigating its own enrollment decline, with current enrollment at roughly 20,140 and projected to drop below 20,000 in fall 2026. The decline is driven largely by an aging population of longtime residents and a limited supply of new single-family homes. As one board member put it: "the acceleration in the declining enrollment really continues to be major." Full calendar at allenisd.org. What Every Collin County Family Should Do Right Now Update emergency contact information through your district's parent portal. Most districts require this annually before school begins. Check immunization requirements. Texas has specific requirements enforced at registration. Schedule appointments now, as pediatric offices get very busy in late July and early August. Order supplies early. Back-to-school supplies sell out at area stores in late July. Order online or shop early. Register new students immediately. Most districts require proof of residency, a birth certificate, immunization records, and previous school records. Processing can take time during peak registration season. Tax-free weekend. Texas holds an annual tax-free weekend in early August applying to most school clothing and supplies under $100. Check comptroller.texas.gov for exact 2026 dates. The enrollment split across Collin County reflects something deeper than school administration. It is a story about which parts of the county are attracting young families with children and which are aging in place — a divide that will shape local politics, school funding, and community investment for years to come.