Horizon Update Discs:
As of 2005, update discs are no longer available. They were originally sold by Horizon Navigation for $125 each. Improvements in the map database content had required an increase in the amount of CDs needed to cover the US from three discs to nine discs. The last software release was version 4.7.2, released September 2004.
1. California / Nevada, USA (P/N NM20-1100101) CA, NV
2. Pacific NW / Mountain, USA (P/N NM20-1100102) AZ, CO, ID, MT, NM, OR, UT, WA, WY, TX
3. Upper Midwest USA (P/N NM20-1100103) IA, KS, MN, MO, NE, ND, SD, plus parts of IL, MI, WI
4. South Central USA (P/N NM20-1100104) AR, LA, MS, OK, plus parts of TN and TX
5. Great Lakes, USA (P/N NM20-1100105) IL, IN, MI, OH, WI
6. Ohio Valley, USA (P/N NM20-1100106) KY, WV plus parts of IN, MD, NY, OH, PA, TN
7. Northeast USA (P/N NM20-1100107) CT, ME, MA, NH, RI, VT, plus parts of NJ, NY
8. Mid Atlantic, USA (P/N NM20-1100108) DE, VA, DC, plus parts of MD, NJ, NC, PA
9. Southeast USA (P/N NM20-1100109) AL, FL, GA, SC, plus parts of NC
