Here's a short list I came up with after a quick google search.
August 2001 - Westmoreland County, PA
Officer, K-9 solve missing woman mystery
Xato cost $3,500, and his training cost an equal amount. Considering equipment and other expenses, a police force spends about $12,500 to put a K-9 officer and dog on patrol.
Along with drug sniffing and other duties, Xato was specially trained to find missing people.
When Yonek and Xato arrived at the missing woman's home, Yonek gave the dog a pair of the missing woman's socks to sniff, and then attached the dog's work collar.
'It's amazing. I get that collar out and it's like a lightbulb goes off in his head and he goes to work,' Yonek said.
The officer then attached the dog's 15-foot tracking leash, gave a command for tracking and searching, and Xato took off - sniffing asphalt and grass as he went.
It took less than five minutes for the dog to find the woman at a construction site on a dirt road, not far from her home.
'She was standing there, disoriented,' Yonek said. 'I started talking to her, saying 'You're all right,' just talking softly, and she started to catch on.'
http://triblive.com/x/pittsburghtrib/news/pittsburgh/s_51411.html#axzz3o8ahSfTD
February 2013 - Macomb County, MI
Deputy’s Tracking Dog Finds Missing Woman with Alzheimer’s
http://www.lifewithdogs.tv/2013/02/deputys-tracking-dog-finds-missing-woman-with-alzheimers/
August 2013 - Polk County, IA
The missing Ankeny woman, Louise G was found Thursday night with the assistance of a tracking dog.
http://whotv.com/2013/08/08/missing-person-ankeny-police-seek-woman-2/
March 2014 - Anderson County, SC
More than 30 people were called in to search for the teen and a bloodhound named Dixie was able to find the girl about a hour later.
http://www.cleveland19.com/story/24800342/tracking-dog-praised-for-finding-missing-teen
July 2014 - Portland, ME
Ruth Brennan, 77, who has dementia, is reunited with relatives after a rescue dog finds her in dense woods in Waterford.
http://www.pressherald.com/2014/07/09/missing-south-portland-woman-found-alive-after-two-day-search/
November 2014 - Tawas, MI
Missing Tawas City girl, 2, found in woods by dog
http://www.freep.com/story/news/local/michigan/2014/11/06/missing-girl-tawas-michigan/18584645/
May 2015 - Apex, NC
K9 call of duty: NC police dog saves missing woman first week on the job
http://myfox8.com/2015/05/24/k9-cal...og-saves-missing-woman-first-week-on-the-job/
August 2015 - Cass County, MI
Missing woman found by police dog
http://www.heraldpalladium.com/news...cle_3a0536f3-c1bd-54aa-bd57-d303bcfefc0c.html
Sept 2015 - Chester County, NC
After Mayfield found her clothes, tracking dogs used their scent to find Lindsey's body behind a neighbor's shed about three hours later.
http://www.wsoctv.com/news/news/local/deputies-investigating-chester-co-womans-suspiciou/nnd7d/