Here are the 2005 Cross Country Divisions from the October CIF Bulletin.
Rather than cross out the schools that normally don't field a team I flagged them with "#" next the their enrollment. An asterick next to the enrollment means the value was doubled because that school is an all-boy or all girls school.

As an aid to meet directors and to make it easier to find a school, here is a sorted list by school name showing division and enrollment.
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Division 1 
9-12 CBEDS 2400 +
2409 Castle Park 2414 Montgomery 2425 Southwest (S.D.)
2444 Mission Hills 2470 Helix Charter 2477 Patrick Henry 2570 Mira Mesa 2572 Eastlake 2579 Bonita Vista 2634 Escondido 2647 Sweetwater 2652 La Costa Canyon 2709 Calexico 2817 Granite Mills 2831 Chula Vista 2849 El Camino 2861 San Diego 2930 Fallbrook 3069 Morse 3070 Rancho Bernardo 3071 Carlsbad 3135 Rancho Buena Vista 3231 Poway 3311 Torrey Pines 3396 Vista
Division 2 
9-12 CBEDS 1900 - 2399

1925 Steele Canyon 1930 University City 1953 Valhalla 1965 El Capitan 1982 Monte Vista 2001 Serra 2003 Ramona 2028 Point Loma 2037 Westview 2065 Otay Ranch 2080 Mt. Miguel 2202 Mt. Carmel 2204 Hoover 2207 Southwest (I.V.) 2216 El Cajon Valley 2221 Mar Vista 2282 San Pasqual 2348 West Hills 2349 Orange Glen 2351 Scripps Ranch 2357 Hilltop 2394 Grossmont 2398 Oceanside
Division 3
9-12 CBEDS 1000-1899

1418* Saint Augustine 1463 Clairemont 1469 Cathedral Catholic 1514 San Dieguito Academy 1520 Valley Center 1521 Madison 1538* Our Lady of Peace 1622 Kearny 1662 San Marcos 1689 La Jolla 1691 Mission Bay 1706 Central Union 1741 Crawford 1779 Santana 1793 San Ysidro 1822 Brawley

Division 4
9-12 CBEDS 350-999

365 La Jolla Country Day 375# Calipatria 275# Canyon Crest Academy 380 Valley 394 Horizon 394 Pruess School 420 Christian 442 Francis Parker 453 High Tech High 481 Mountain Empire 497 Bishop's School 574* Army-Navy Academy 577 Holtville 650 Marian Catholic 708 Guajome Park Academy 754# Imperial 874 Palo Verde 901 Escondido Charter 927 Gompers Secondary 945 Coronado

Division 5
9-12 CBEDS 349 and less


9#    South Bay Christian
20#   All Tribes American Indian
36#   Torah High Schools of San Diego 
53#   H-Town Christian Academy
65    Christian Life Academy
67#   Sun Valley Charter
81#   Calvary Christian (C.V.)
84    CCPAA
92#   San Diego Academy
102   Lutheran
102#  Warner
108#  San Pasqual Academy
111#  Escondido Adventist Academy
114#  Midway Babtist
120#  River Valley
130   Calvary Christian (Vista)
139#  West Shores
147   San Diego Jewish Academy
159   Borrego Springs
197#  Venture Christian
223#  Aurora
227   Calvin Christian
238   Julian
258   Vincent Memorial
295   Tri-City Christian
348   Santa Fe Christian