This lists the first two zip code numbers for each state and its bordering states. e.g., the NY list includes "10", found in Manhattan as well as "07", found in NJ.

zip-prefix-adjacency

WA = 99 83 97 98
DE = 15 21 17 16 19 18 08 20 07
DC = 24 20 21 22 23
WI = 48 49 55 54 56 51 50 53 52 60 61 62
WV = 24 25 23 15 21 17 16 19 18 44 45 22 43 40 41 26 20 42
HI = 96
FL = 39 33 32 31 30 36 35 34
WY = 59 57 82 83 68 69 80 81 84
NH = 02 03 01 04 05
NJ = 11 10 13 12 15 14 17 16 19 18 08 07
NM = 78 88 77 76 75 74 73 79 80 81 86 87 84 85
TX = 75 77 76 88 74 73 72 71 70 87 79 78
LA = 39 38 88 77 76 75 73 72 71 70 79 78
AK = 99
NC = 24 39 38 20 22 23 28 31 30 37 29 27
ND = 55 57 56 59 58
NE = 57 51 50 52 68 63 64 65 66 67 82 83 80 81 69
TN = 24 39 27 20 22 23 63 28 31 30 42 36 40 41 65 38 64 35 71 37 72
NY = 02 10 13 01 15 07 17 16 19 18 08 05 12 11 06 14
PA = 11 10 13 12 20 14 17 25 19 18 08 45 21 43 16 26 24 15 44 07
RI = 02 01 06 05
NV = 95 88 96 89 97 90 91 83 93 92 86 94 84 85
VA = 24 25 26 27 20 21 22 23 28 42 37 40 41 38
CO = 86 68 88 74 73 66 67 82 83 80 81 69 87 84 85
CA = 96 95 88 89 91 90 93 92 86 94 97 85
AL = 39 38 33 32 31 30 37 36 35 34
AR = 39 38 74 37 88 77 76 75 63 64 65 71 70 73 72 79 78
VT = 11 10 13 12 14 03 02 01 05
IL = 51 46 47 42 50 40 41 60 61 62 63 64 65 54 52 53
GA = 39 38 33 32 31 30 37 36 35 34 27 29 28
IN = 48 49 46 47 44 45 42 43 40 41 60 61 62
IA = 55 54 57 56 51 50 53 52 60 61 62 63 64 65 68 69
MA = 02 10 13 12 06 14 03 05 01 11
AZ = 81 80 86 85 87 88 89 91 90 93 92 95 94 84 96
ID = 59 99 98 88 89 97 82 83 84
CT = 11 10 13 12 06 14 05 02 01
ME = 03 04
MD = 24 25 26 20 17 22 23 19 18 16 15 21
OK = 81 66 74 88 77 76 75 63 64 65 71 67 73 80 78 87 79 72
OH = 24 25 26 45 15 48 17 16 19 18 44 49 42 43 40 41 46 47
UT = 88 89 82 83 80 81 86 87 84 85
MO = 37 60 61 62 63 64 65 66 67 68 69 42 40 41 74 73 72 71 38 51 50 52
MN = 58 55 54 57 56 51 50 53 52
MI = 48 49 46 54 44 45 43 53 47
KS = 63 64 65 66 67 68 69 80 81 73 74
MT = 82 83 57 59 58
MS = 39 38 37 36 35 72 71 70
SC = 39 27 31 30 28 29
KY = 60 61 62 63 64 65 24 25 26 20 22 23 46 47 44 45 42 43 40 41 38 37
OR = 99 98 88 89 83 91 90 93 92 95 94 97 96
SD = 59 58 55 57 56 51 50 52 82 83 68 69