The Sōma Nakamura Domain (相馬中村藩, Sōma Nakamura han) was a minor feudal domain under the Tokugawa shogunate of Edo period Japan based in southern Mutsu Province in what is now part of the Hamadōri region of modern-day Fukushima Prefecture.

During early Kamakura period, the Sōma clan served as retainers of Minamoto no Yoritomo and were awarded lands in southern Mutsu Province for their role in the conquest of Hiraizumi in 1189.

During the Battle of Sekigahara, he did not respond to Tokugawa Ieyasu, as the Satake clan had decided to side with the pro-Toyotomi western army under Ishida Mitsunari.

During the last Edo period, the domain began to implement the Hōtoku agricultural reforms originated by Ninomiya Sontoku.

Unlike most domains in the han system which consisted of several discontinuous territories calculated to provide the assigned kokudaka, based on periodic cadastral surveys and projected agricultural yields.,[2][3] Sōma Nakamura Domain consisted of a single unified territory covering what is now the modern municipalities of Sōma, Minamisōma, Futaba, Namie, Ōkuma and Iitate as well as most of Shinchi in what is now Fukushima Prefecture.

During the Battle of Sekigahara, he attempted to remain neutral, as his father was on close terms with Ishida Mitsunari and as he had concerns with regards to his powerful neighbors, the Satake clan.

A number of senior Tokugawa retainers spoke out on his behalf, including Honda Masanobu, and the Sōma clan's traditional rival, Date Masamune.

He was the eldest son of Sōma Toshitane, and his mother was an adopted daughter of Shogun Tokugawa Hidetada.

He became daimyō at the age of 7 in 1625 on the death of his father, and due to his youth, his uncle Sōma Yoshitane served as regent.

In 1641, during a great fire in Edo, he was ordered by the shogunate to oversee firefighting efforts, but was seriously injured when a horse panicked.

He was presented in formal audience to Shogun Tokugawa Tsunayoshi as the son of Satake Yoshizumi in December 1692, and was adopted into the Sōma clan in July 1696.

In 1696, the childless Masatane adopted Nobutane, a younger son from the Satake clan, as his heir, but Takatane was born the following year.

In January 1751 named Tokutane's heir, and was presented in formal audience to shōgun Tokugawa Ieshige a month later.

Although he was born in 1765, when he was appointed heir to the domain in 1774, the clan reported his birth year to have been 1761, so that he would not be considered to be underage.

He was presented in formal audience to shōgun Tokugawa Ieharu in June 1775 and granted the courtesy title of Sanuki-no-kami.

The domain was unable to repay the loan as agreed, and Yoshitane was ordered to step down in favor of his son Muratane.

He was the eldest son of Sōma Yoshitane, and his mother was a daughter of Matsudaira (Sakurai) Tadatsugu of Amagasaki Domain.

He was presented in formal audience to shōgun Tokugawa Ienari in November 1798 and granted the courtesy title of Sanuki-no-kami.

From 1817, he took steps to reform the domain's finances, and he retired in March 1835 in favor of his eldest son, Michitane.

In February 1833, he was presented in formal audience to shōgun Tokugawa Ienari and subsequently received the courtesy title of Daizen-no-suke.

He was presented in formal audience to shōgun Tokugawa Ieshige in March 1865, and became daimyō when his brother retired a few months later.

During the Bakumatsu period, he initially attempted to remain neutral in the Boshin War, as the domain had negligible military forces.

The Satchō Alliance forced advanced through the Hamadōri region and captured Sōma Nakamura Castle with only token resistance a few months later.

On 14 April 1879, Tomotane was placed under house arrest by the government, after family members filed a petition accusing him of mental instability.

On 10 December 1885, one of his former retainers, Nishigori Takekiyo, filed a lawsuit accusing these relatives, led by Toshitane's younger brother, Sōma Aritane, of having made false charges leading to Tomotane's incarceration, for the purposes of embezzling the monies of the former domain.

The Sōma clan hired the famous lawyer Hoshi Tōru to defend their case, which went on for years, as the legal definition of insanity and the qualifications necessary for a doctor to declare a person mentally incompetent were not yet defined in Japanese jurisprudence.

However, after an autopsy failed to find any evidence, Nishikori was countersued for slander and was sentenced to four years in prison.