City

Population (2010)

Height above sea level (m)

Geographic location of sampling sites

Agua Prieta

79,138

1220

31˚18'41.76''N 109˚32'07.33''W

Nogales

220,292

1238

31˚19'28.58''N 110˚57'18.44''W

Puerto Peñasco

57,342

10

31˚20'30.29''N 113˚30'58.46''W

Hermosillo

784,382

227

29˚02'38.50''N 110˚57'27.80''W

Guaymas

149,299

20

27˚54'51.53''N 110˚54'11.91''W

Obregón

409,310

61

27˚29'01.92''N 109˚56´51.93''W