List of extreme latitudes and longitudes for each US state?

If you're just looking for extreme values of x/y coordinates, you could use QGIS with this expression (e.g. in the field calculator): x_max( $geometry) - replace x with y and max with min for the according values.

1. Download a vector file for US states, e.g. from OpenStreetMap. There are different ways to do than, one is using Overpass Turbo.

2. Create a bounding box around each state.

3. Calculate the centroid of the bounding box and you're done.

Screenshot: Vector shape of Texas with red bounding box. White dot: centroid of Texas polygon, red dot: centroid of bounding box.

If you're looking for data, please try https://opendata.stackexchange.com/.

Two expressions in QGIS will give you exactly what you want:

( y_min( $geometry ) + y_max( $geometry ) ) / 2

( x_max( $geometry ) + x_min( $geometry ) ) / 2

I will post and expand upon the answer provided by JonasV in his comment to the original post. If JonasV wants to post an answer, I would be happy to mark that as the answer. Based on his answer, here are two web sites with the data I was looking for:

TONY - https://anthonylouisdagostino.com/bounding-boxes-for-all-us-states/ - has 56 states and territories – Texas extreme longitudes are -106.645646 and -93.508292

MISHARI - https://gist.github.com/mishari/5ecfccd219925c04ac32 – has 48 states (eg, missing AK) – Texas extreme longitudes are -106.645652770996 and -93.5078201293945

For comparison, Wikipedia Texas extreme longitudes are -106.645657 and -93.507969 - https://en.wikipedia.org/wiki/List_of_extreme_points_of_U.S._states_and_territories

I have no idea why the extreme longitudes (bounding boxes) are (very slightly) different in the three sources. The differences are evidently not rounding errors.

TONY has bounding boxes for basically all the states and territories, so that is the best choice. Here are the data exactly as posted on the TONY web site in CSV format for importing into a spreadsheet:

"","STATEFP","STUSPS","NAME","xmin","ymin","xmax","ymax"
"1","01","AL","Alabama",-88.473227,30.223334,-84.88908,35.008028
"2","02","AK","Alaska",-179.148909,51.214183,179.77847,71.365162
"3","60","AS","American Samoa",-171.089874,-14.548699,-168.1433,-11.046934
"4","04","AZ","Arizona",-114.81651,31.332177,-109.045223,37.00426
"5","05","AR","Arkansas",-94.617919,33.004106,-89.644395,36.4996
"6","06","CA","California",-124.409591,32.534156,-114.131211,42.009518
"7","08","CO","Colorado",-109.060253,36.992426,-102.041524,41.003444
"8","69","MP","Commonwealth of the Northern Mariana Islands",144.886331,14.110472,146.064818,20.553802
"9","09","CT","Connecticut",-73.727775,40.980144,-71.786994,42.050587
"10","10","DE","Delaware",-75.788658,38.451013,-75.048939,39.839007
"11","11","DC","District of Columbia",-77.119759,38.791645,-76.909395,38.99511
"12","12","FL","Florida",-87.634938,24.523096,-80.031362,31.000888
"13","13","GA","Georgia",-85.605165,30.357851,-80.839729,35.000659
"14","66","GU","Guam",144.618068,13.234189,144.956712,13.654383
"15","15","HI","Hawaii",-178.334698,18.910361,-154.806773,28.402123
"16","16","ID","Idaho",-117.243027,41.988057,-111.043564,49.001146
"17","17","IL","Illinois",-91.513079,36.970298,-87.494756,42.508481
"18","18","IN","Indiana",-88.09776,37.771742,-84.784579,41.760592
"19","19","IA","Iowa",-96.639704,40.375501,-90.140061,43.501196
"20","20","KS","Kansas",-102.051744,36.993016,-94.588413,40.003162
"21","21","KY","Kentucky",-89.571509,36.497129,-81.964971,39.147458
"22","22","LA","Louisiana",-94.043147,28.928609,-88.817017,33.019457
"23","23","ME","Maine",-71.083924,42.977764,-66.949895,47.459686
"24","24","MD","Maryland",-79.487651,37.911717,-75.048939,39.723043
"25","25","MA","Massachusetts",-73.508142,41.237964,-69.928393,42.886589
"26","26","MI","Michigan",-90.418136,41.696118,-82.413474,48.2388
"27","27","MN","Minnesota",-97.239209,43.499356,-89.491739,49.384358
"28","28","MS","Mississippi",-91.655009,30.173943,-88.097888,34.996052
"29","29","MO","Missouri",-95.774704,35.995683,-89.098843,40.61364
"30","30","MT","Montana",-116.050003,44.358221,-104.039138,49.00139
"31","31","NE","Nebraska",-104.053514,39.999998,-95.30829,43.001708
"32","32","NV","Nevada",-120.005746,35.001857,-114.039648,42.002207
"33","33","NH","New Hampshire",-72.557247,42.69699,-70.610621,45.305476
"34","34","NJ","New Jersey",-75.559614,38.928519,-73.893979,41.357423
"35","35","NM","New Mexico",-109.050173,31.332301,-103.001964,37.000232
"36","36","NY","New York",-79.762152,40.496103,-71.856214,45.01585
"37","37","NC","North Carolina",-84.321869,33.842316,-75.460621,36.588117
"38","38","ND","North Dakota",-104.0489,45.935054,-96.554507,49.000574
"39","39","OH","Ohio",-84.820159,38.403202,-80.518693,41.977523
"40","40","OK","Oklahoma",-103.002565,33.615833,-94.430662,37.002206
"41","41","OR","Oregon",-124.566244,41.991794,-116.463504,46.292035
"42","42","PA","Pennsylvania",-80.519891,39.7198,-74.689516,42.26986
"43","72","PR","Puerto Rico",-67.945404,17.88328,-65.220703,18.515683
"44","44","RI","Rhode Island",-71.862772,41.146339,-71.12057,42.018798
"45","45","SC","South Carolina",-83.35391,32.0346,-78.54203,35.215402
"46","46","SD","South Dakota",-104.057698,42.479635,-96.436589,45.94545
"47","47","TN","Tennessee",-90.310298,34.982972,-81.6469,36.678118
"48","48","TX","Texas",-106.645646,25.837377,-93.508292,36.500704
"49","78","VI","United States Virgin Islands",-65.085452,17.673976,-64.564907,18.412655
"50","49","UT","Utah",-114.052962,36.997968,-109.041058,42.001567
"51","50","VT","Vermont",-73.43774,42.726853,-71.464555,45.016659
"52","51","VA","Virginia",-83.675395,36.540738,-75.242266,39.466012
"53","53","WA","Washington",-124.763068,45.543541,-116.915989,49.002494
"54","54","WV","West Virginia",-82.644739,37.201483,-77.719519,40.638801
"55","55","WI","Wisconsin",-92.888114,42.491983,-86.805415,47.080621
"56","56","WY","Wyoming",-111.056888,40.994746,-104.05216,45.005904

I have already incorporated the data into the software I write, in data arrays. It all works automatically / perfectly, all the state maps are exactly centered now.