Human Names in Star Trek
We know that human personnel is prevalent in Starfleet. Moreover, most of those humans are established as, or can supposed to be Americans. But it also seems that, irrespective of their skin color, the overwhelming majority of supporting characters and extras are of English, Scottish or Irish origin, as indicated by their casually mentioned last names. The same applies to the first names as far as they are known. The situation has worsened since Enterprise, a series in which there seems to exist no non-US humanity at all, at least not on starships.
The following list classifies the human last names mentioned in Star Trek until about 2005 (main source: Encyclopedia III), not including those of holographic and other fictional characters and of individuals from a time before 2100 when nation states still existed.
British/Irish (including now typical English names of Norman and Norwegian origin)
Adams, April, Archer, Arkinson, Ashmore, Bailey, Ballard, Barclay, Barnaby, Barron, Barrows, Barstow, Bartlett, Barton, Bates, Bateson, Baxter, Bennet, Bennett, Benton, Bernard, Biddle, Bilby, Blackwell, Blain, Bogrow, Boone, Boothby, Boyce, Boylan, Boylen, Brackett, Briggs, Bristow, Brooks, Brower, Brown, Bullock, Burke, Byrd, Cabot, Calloway, Carey, Carrington, Carson, Carstairs, Cartwright, Casey, Channing, Chapel, Chapman, Cheney, Childress, Chilton, Christopher, Clancy, Clark, Clendenning, Cogley, Coleman, Colt, Collins, Conor, Corbin, Corrigan, Crater, Crusher, Culhane, Curtis, Dalby, Darnell, Darson, Darvin, Darwin, Davies, Davis, Dean, Decker, Delaney, Dickerson, Douglas, Doyle, Duffy, Eddington, Edwell, Evans, Evansville, Farrell, Felton, Finnegan, Finney, Fisher, Fitzpatrick, Fletcher, Forrest, Fox, Franklin, Freeman, Fullerton, Garrett, Garrovick, Garth, Gentry, Gibson, Giddings, Gill, Gillespie, Gladstone, Gleason, Gordon, Gossett, Grady, Graham, Granger, Graves, Grayson, Green, Haines, Hanson, Hargrove, Harper, Harriman, Harris, Harrison, Haskins, Hawk, Hawkins, Hayes, Hayne, Hedford, Hendrick, Hengist, Henley, Henry, Henshaw, Hickman, Hill, Hobson, Hogan, Howard, Hubble, Hudson, Hutchinson, Jackson, Jameson, Janeway, Jarvis, Jellico, Jenkins, Johnson, Jones, Keel, Keeler, Keene, Kelly, Kelsey, Kennelly, Keogh, Kingsley, Kirby, Kirk, Kirkby, Kyle, Larson, Lawton, Leighton, Leonard, Lester, Lewis, Leyton, Locklin, Logan, Lyman, Lynch, MacAlister, MacAllister, MacDougal, MacDuff, Macormak, Maddox, Mallory, Markson, Marple, Marvick, Masters, Matthews, Maxwell, Mayweather, McCauley, McClukridge, McConnell, McCoullough, McCoy, McDowell, McFarland, McGarry, McGivers, McHuron, McKenzie, McKinney, McKnight, McLaren, McMinn, McWatt, Mears, Merrick, Miller, Minnerly, Mitchell, Molson, Moore, Morrow, Mudd, Mulhall, Murphy, Neeley, Neil, Nelson, Norris, O'Brien, O'Connell, O'Donnell, O'Neil, O'Neill, Palmer, Parsons, Pauley, Peeples, Pendleton, Piper, Porter, Potts, Powell, Quinn, Quint, Ramsey, Rawlens, Rayburn, Raymond, Reed, Reel, Reese, Remmick, Reynolds, Rhodes, Rice, Riker, Riley, Robertson, Robinson, Rogers, Rollins, Rollman, Rooney, Ross, Russell, Ryan, Ryson, Sanders, Scott, Seaborn, Shepard, Shaw, Shea, Shelby, Smith, Starnes, Stevens, Stiles, Stocker, Stone, Strickler, Stubbs, Sturgeon, Styles, Sullivan, Sutter, Swift, Swinn, Swofford, Taggert, Terrell, Thompson, Thorne, Tomlinson, Tracey, Travers, Tucker, Tyler, Underhill, Varley, Walker, Wallace, Warren, Washburn, Watkins, Watley, Watters, Wesley, Whatley, Wildman, Wilkins, Williams, Wilson, Willoughby, Wright, Wrightwell, Yates, Young
Rest of the world (Spanish, Italian, Scandinavian, German, Jewish, Polish, Russian and very few "exotic" names)
Anderson, Anthwara, Aquino, Arriaga, Atoa, Ayala, Baris, Bashir, Bendera, Berlin, Bertram, Beaumont, Bilecki, Boma, Brahms, Brevelle, Brianon, Bronovski, Chakotay, Chang, Chekote, Chekov, Colti, Cusak, D'Sora, Davila, Dehner, DeSalle, DeSeve, DeSoto, Diego, Dumont, Eiger, Esteban, Giger, Giotto, Girani, Giusti, Hagen, Hansen, Hastur, Helewa, Hendorff, Hildebrandt, Jaeger, Juarez, Kalomi, Karidian, Kenicki, Kelowitz, Kim, Kopf, Kosinski, Krajensky, Kyoto, Kwan, Lakanta, La Forge, Linke, Lin, Lindstrom, Loews, Lopez, Louvois, M'Benga, Malencon, Mandel, Mandl, Manheim, Mannus, Marquez, Masada, Mendez, Meyer, Molina, Moreau, Mulchaey, Muniz, Nakamura, Narsu, Ngomo, Nicoletti, Noel, Nogura, Novakovich, Nozawa, Ogawa, Palamas, Paris, Pavlick, Pechetti, Picard, Pulaski, Quintana, Quinteros, Ramirez, Rhada, Rodriguez, Romaine, Rozhenko, Sanchez, Santos, Sato, Schmitter, Seyetik, Singha, Sisko, Spinelli, Sulu, T'su, Tannenbaum, Tessoni, Thule, Torres, Trumari, Tsingtao, U'Lanai, Uhura, Van Doren, Van Mayter, Van Gelder, Vanderberg, Vassbinder, Vigo, Wagner, Weiss, Wong, Woo, Yar, Yosa, Ziegler
Uncertain or multiple possibilities
Aaron, Albert, Arton, Aster, Barnhart, Bartel, Baytart, Beck, Benbeck, Bensen, Benteen, Brack, Branch, Brand, Brink, Brossmer, Cavit, Cobum, Corbin, Cory, Daren, Daystrom, Dern, Drazman, Dulmer, Durst, Emmanuel, Farris, Ferris, Flint, Galen, Gilhouly, Haden, Haftel, Hagler, Herbert, Holt, Horne, Jonas, Joseph, Kaplan, Kayden, Kelso, Korby, Lasca, Lang, Latimer, Lavelle, Lazarus, Lefler, Leijten, Lemli, Lense, Lessing, Lucier, Lucsly, Marr, Martin, Martine, Mendrossen, Menegay, Mullen, Mowray, Nara, Niles, Phillips, Pierce, Piersall, Pierse, Ramart, Ranar, Rand, Rifkin, Sandoval, Satie, Sharr, Sophen, Supera, Taitt, Telfer, Tormolen, Valtane, Wade, Zielen, Zweller
I may have missed several names and I probably made some mistakes in linking them to countries (no need to e-mail me about every possible error), but it shows how predominant the writers have rendered the British/Irish heritage. No present-day American phone book has such a low share of non-British/Irish names, even if we take into consideration that immigrants often allowed themselves to be assimilated by changing their names like from "Schmidt" to "Smith".
There may be different reasons for the observation that some 60% of all human names in Star Trek are British or Irish. To a North American audience a name with the pattern "McSomething" sounds more concise and overall a lot cooler than "Papadopoulos", for instance. Also, thanks to Hollywood's obstinate adherence to the Nazi stereotype everyone expects that a good guy has to be named "Smith" and never "Schmidt". But this is a weak apology for the Anglification of the world, for a silly habit of most authors, who apparently pick their characters' names from a book of British/Irish genealogy, entirely ignoring the true composition of the world population in general and even of white American citizens in particular. Together with the observation that American places, customs and food are all-dominant in the fictional future, this more or less defies Star Trek's intention to show how humanity may live in peace and explore space together.
Thanks to Gregory Price for adding several names to the list.