This was a lot of work. My source was the 2000 Texas Tech Alumni Directory. A questionnaire was sent to all known addresses in 1999 & those that were returned were included in the directory. 147,000 names are in that directory.

My source for total students having attended Tech each decade is various La Ventana's I've collected. We'll start with a total student SWAG. I'll take the average annual enrollment per decade & multiply it by 2.5 to get a total for that decade (each class stays 4 years making 2 1/2 units [4+4+2] for each 10 years).

1950's 10,000 students x 2.5 = 25,00

1960's 12k in 1964/18,000 in 1968 = 38,000

1970's 26,000 students x 2.5 = 65,000

1980's 28,000 students x 2.5 = 70,000

1990's 30,000 students x 2.5 = 75,000

2000's 33,000 students x 2.5 = 82,500

Rough total of living persons who went to Texas Tech 

355,500

Total in 2000 Alumni directory 147,000

355,500 / 147,000 = 2.42 We will multiply this by all known numbers from the 2000 directory to get a total number.

6 County Dallas/Ft Worth Metropolitan Area - Tech alums in the 2000 directory by county

Dallas - 13,777

13,777 x 2.42 = 33,340

Tarrant - 6,130

6130 x 2.42 = 14,834

Collin - 3788

3788 x 2.42 - 9,167

Denton - 1975

1975 x 2.42 = 4,780

Ellis, Rockwall - 705

705 x 2.42 = 1,706

Those were the counts in 2000. Here are the county growth rates between 2000 and 2010 census:

http://www.star-telegram.com/2011/02/17/2858363/search-more-than-38-percent-of.html

Dallas 6.73%

Tarrant 25.1%

Collin 59.12%

Denton 53.04%

Ellis 31.04%

 

So assuming Red Raiders moved from elswhere into the Metroplex at the same rate as the rest of the population the 2000 counts multiplied by the growth rates will look like this:

Dallas County 33,340 x 1.0673 = 35,584

Tarrant County 14,834 x 1.251 = 18,557

Collin County 9,167 x 1.5912 = 14,587

Denton County 4780 x 1.5304 = 7,315

Ellis/Rockwall Counties 1706 x 1.3104 = 2,236

 

Scientific Wild Ass Guess (SWAG) as to the number of living persons in the Dallas/Ft Worth Metro area who enrolled at Texas Tech:

78,279

 

Add wives, husbands, children & friends who Tech alums have infected with Raider mania & 100,000 Tech fans is probably about right. 

Detailed city numbers from the 2000 Directory after the jump.

Addison - 73

Allen - 432

Arlington - 1901

Bedford - 444

Carrolton - 914

Cedar Hill - 142

Colleyville - 280

Coppell - 516

Dallas - 6611

Denton - 374

DeSoto - 166

Duncanville - 200

Ueless - 220

Farmers Branch - 50

Flower Mound - 432

Ft Worth - 2800

Frisco - 380

Garland - 840

Grand Prairie - 310

Grapevine - 360

Highland Village - 80

Irving - 972

Keller - 225

Mansfield - 200

McKinney - 492

Mesquite - 373

N Richland Hills - 180

Plano - 2376

Richardson - 1150

Raonoke - 60

Rockwall - 230

Rowlett - 283

Southlake - 226

Terrell - 75

Colony - 88

Trophy Club 75

Waxahatchie - 400

Wylie - 108