New York
Someone will jump in and correct/clarify, (a) because it's confusing and (b) because we're from New York.
New York has two state meets. The first is the New York State Public High School Athletic Association championship (NYSPHSAA).
NYSPHSAA has eleven regions called Sections. It covers all of NYS except for NYC, which is separate (more later). Private/independent, parochial, and non-parochial religious schools *typically* compete in separate leagues Downstate (with some exceptions) and some compete in the NYSPHSAA Upstate (again with exceptions).
Each Section determines its own standards for qualification to the Sectional Championship/State Qualifier. All State Qualifier races are organized by school size into classes (currently 4: A, B, C, D, but it's been five, it's been three, etc.). This works out well in many Sections that have large numbers of schools of all sizes, but in some Sections the largest schools race or the smallest schools race may be non-competitive or non-existent. NYS needs to account for the range of the school sizes across the state, but it's so internally diverse by population density and school size that locally the classifications don't always make as much sense as they do statewide.
At each Sectional Championship/State Qualifier, the top team in each class advances (7 runners) plus the top 5 runners not on the top team. These runners then compete at the NYSPHSAA meet where for many years they wore color-coded t-shirts instead of singlets and competed not just for their team but for their Section as a whole.
On the same day as the NYSPHSAA championship, there are three other championship races of varying competitiveness: the CHSAA (Catholic High Schools, mostly but not exclusively Downstate), the PSAL (NYC public schools), and the NYSAIS (mostly but not exclusively NYC/NYC area independent schools).
These four championship meets determine who will advance to the Federation Championship held the next weekend. NYSPHSAA automatically advances 9 teams (selection across classes can become convoluted), CHSAA Upstate automatically advances 1 team, CHSAA automatically advances 3 teams, PSAL automatically advances 3 teams, and the AIS automatically advances 1 team. Once those teams are determined, NYSPHSAA Section officials and coaches select an additional 7 teams (these can be the next-top-placing teams at the NYSPHSAA meet or top-quality teams that didn't advance out of their State Qualifier because the top team in the state was their close-in-size neighbor). The CHSAA, PSAL, and AIS split 3 at-large teams between them (at least two usually go to the CHSAA). By this point there are 27 teams for boys and girls entered in the Federation meet.
Now onto individuals. Individuals not on any of the qualifying teams are proportioned accordingly for a total of 70 individuals:
NYSPHSAA: 40
CHSAA Upstate: 3
CHSAA: 12
PSAL: 12
AIS: 3
For the CHSAA, PSAL, and AIS it's usually just the top individuals at each of the championships, but it gets more complicated at NYSPHSAAs across all four classes, and usually there is some effort to make sure that at least one individual from each Section advances if they had not otherwise qualified, so sometimes that's the top runner at a State Qualifier meet even if they weren't the top finisher at NYSPHSAAs.
The Fed meet has been hampered of late because it's held late in the season and close to both NXN New York and Footlocker Northeast, so many top teams have begun to skip the meet to rest up for the following weekend. Unlike the NYSPHSAA meet that moves across the state, Feds is always held in the same not-really-that-central location every year, so for teams that are proximate travel is easy, but for public school teams that may have already traveled from Buffalo to Westchester for the NYSPHSAA meet, it can be difficult to justify the travel time, travel cost, and travel fatigue to drive all the way back to Bowdoin Park in Wappingers Falls (north of Westchester but similarly far east).