Question: Landon T. Clay (born Landon Thomas Clay) was an American businessman and founder of the Clay Mathematics Institute (CMI),  a private, non-profit foundation, based in Peterborough, New Hampshire, in which country?
Context: The Clay Mathematics Institute (CMI) is a private, non-profit foundation, based in Peterborough, New Hampshire, United States.  CMI's scientific activities are managed from the President's office in Oxford, United Kingdom.  The institute is "dedicated to increasing and disseminating mathematical knowledge."  It gives out various awards and sponsorships to promising mathematicians.  The institute was founded in 1998 through the sponsorship of Boston businessman Landon T. Clay.  Harvard mathematician Arthur Jaffe was the first president of CMI. In mathematical physics, the Yang–Mills existence and mass gap problem is an unsolved problem and one of the seven Millennium Prize Problems defined by the Clay Mathematics Institute, which has offered a prize of US$1,000,000 to the one who solves it. Clay Mathematics Monographs is a series of expositions in mathematics co-published by AMS and Clay Mathematics Institute.  Each volume in the series offers an exposition of an active area of current research, provided by a group of mathematicians. Chinese Maritime Institute also called China Maritime Institute (CMI) was founded on July 11, 1962, and it is a non-profit institute based in the Taipei City, Taiwan.  CMI's main mission is to promote and to engage in academic research on maritime and aviation research and to co-fund the publication of Maritime Quarterly journal in Taiwan.  The founding chairman of CMI is the late Professor Kuang Wang.  The late Professor Kuang Wang was a leading academic researcher and god father on maritime domain in both China and Taiwan.  CMI together with CMRI (Chinese Maritime Research Institutes) is one of the major maritime research organizations in Taiwan.  The permanent president of honour for CMI is Prof. Kuan Lin who is also the founder of one of the largest logistics companies, Pacific Star Group, in Taiwan.  Dr. Kuan Lin together with his wife, Ms. Ivy Wang, donated a six storey building, the Ivy Hall, to the National Taiwan Ocean University in 2011.  Current chairman of the CMI is Professor Chih-Ching Chang of the National Taiwan Ocean University.  Professor C.C. Chang was also the deputy president of the National Taiwan Ocean University between May 2011 and July 2012.  The 17th Board members of CMI will held their posts for three years from May 27, 2011 until May 26, 2014. Tian Gang (; born November 1958) is a Chinese-American mathematician and an academician of the American Academy of Arts and Sciences.  He is known for his contributions to geometric analysis and quantum cohomology especially Gromov-Witten invariants, among other fields.  He was born in Nanjing, and was a professor of mathematics at MIT from 1995–2006 (holding the chair of Simons Professor of Mathematics from 1996), but now divides his time between Princeton University and Peking University.  His employment at Princeton started from 2003, and now he is entitled Higgins Professor of Mathematics; starting 2005, he has been the director of Beijing International Center for Mathematical Research (BICMR); he has also been Dean of School of Mathematical Sciences, Peking University since 2013.  He with John Milnor involved as Senior Scholars of The Clay Mathematics Institute (CMI).  Since 2011, Gang Tian become director of Sino-French Research Program in Mathematic in "le Centre National de la Recherche Scientifique"(CNRS) in Paris.  Since 2010, He became Scientific council for International Center for Theoretical Physics in Trieste in Italy. The Clay Research Award is an annual award given by the Oxford-based Clay Mathematics Institute to mathematicians to recognize their achievement in mathematical research.  The following mathematicians have received the award: The Millennium Prize Problems are seven problems in mathematics that were stated by the Clay Mathematics Institute in 2000.  The problems are Birch and Swinnerton-Dyer conjecture, Hodge conjecture, Navier–Stokes existence and smoothness, P versus NP problem, Poincaré conjecture, Riemann hypothesis, and Yang–Mills existence and mass gap.  A correct solution to any of the problems results in a US $1 million prize being awarded by the institute to the discoverer(s). In mathematics, the Hodge conjecture is a major unsolved problem in the field of algebraic geometry that relates the algebraic topology of a non-singular complex algebraic variety and the subvarieties of that variety.  More specifically, the conjecture says that certain de Rham cohomology classes are algebraic, that is, they are sums of Poincaré duals of the homology classes of subvarieties.  It was formulated by the Scottish mathematician William Vallance Douglas Hodge as a result of a work in between 1930 and 1940 to enrich the description of de Rham cohomology to include extra structure that is present in the case of complex algebraic varieties.  It received little attention before Hodge presented it in an address during the 1950 International Congress of Mathematicians, held in Cambridge, Massachusetts, U.S.  The Hodge conjecture is one of the Clay Mathematics Institute's Millennium Prize Problems, with a prize of $1,000,000 for whoever can prove or disprove the Hodge conjecture. Landon T. Clay (born Landon Thomas Clay) was an American businessman and founder of the Clay Mathematics Institute.  He died on July 29, 2017 In mathematics, the Birch and Swinnerton-Dyer conjecture describes the set of rational solutions to equations defining an elliptic curve.  It is an open problem in the field of number theory and is widely recognized as one of the most challenging mathematical problems.  The conjecture was chosen as one of the seven Millennium Prize Problems listed by the Clay Mathematics Institute, which has offered a $1,000,000 prize for the first correct proof.  It is named after mathematicians Bryan Birch and Peter Swinnerton-Dyer who developed the conjecture during the first half of the 1960s with the help of machine computation.  s of 2016 , only special cases of the conjecture have been proved.
Answer: United States