In August 1878 the land known today as the Te Aroha Hot Springs Reserve was made a public reserve under the Public Domains Act on December 1882. The consent of local Maori and in particular the Morgan family to Government plans for the establishment of such a reserve was of critical importance and it was through their generosity in giving up the land that the Domain became what it is today.

The possibility of a 'sanatorium' being developed at Te Aroha had been envisaged as early as the 1870s, as regular excursions were conducted from Thames to Te Aroha by boat during this time so that visitors could take advantage of the hot springs. In February 1880 a regular boat service with the Mem Sahib was begun between Paeroa and Te Aroha while the Vivid ran between Thames and Paeroa, and in November that year a coach service was established between Hamilton and Te Aroha.

The construction of the first permanent Bath Houses began in 1883. By this time the hot springs were becoming well known as a tourist resort. The railway from Hamilton to Te Aroha was opened in March 1886 completing the link from Auckland and greatly increasing its accessibility and popularity for visitors.

The town of Te Aroha was developing rapidly at this time and it was visitors to the hot pools that were bringing prosperity to be town rather than the profits of local gold mining. In August 1885 the initial landscape development began including manicured lawns, provision for croquet, lawn tennis and racket courts, and tree planting. Further springs were being opened and the paths were beginning to be constructed linking the new features.

Apart from the pleasures and benefits of the hot springs and the Domain itself, visitors enjoyed visits to the mines, to the Waiorongomai battery, walks to the top of Mount Te Aroha and trips up the river to picnic spots. By now there were three large hotels, The Palace, the Te Aroha and the Hot Springs and two boarding houses, altogether providing accommodation for 500 visitors. In the year ended 31 March 1887, 28,553 baths were taken at Te Aroha. By way of comparison, Rotorua had 4,878 taken over the same period.

The spa helped protect Te Aroha from the effects of the long depression of the late 1880s and early 1890s. By the 1890s Te Aroha had become the most popular Spa in the country. In 1889 the railway link from Thames to Te Aroha was completed giving visitors from Auckland two travel options to the spa: by rail through Hamilton, or by boat from Auckland to Thames and from there by rail.

On Queen Victoria’s birthday, 24 May 1898 Hon. A J Cadman, Minister for Railways and Mines, opened the Cadman Bath House. The building measured 30m long by 8.5m wide with private baths and a central corridor 2.4m wide. A new band rotunda was also erected. By the turn of the century 22 springs had been discovered in The Domain, 15 of which were hot.

By 1901 the Hot Springs Domain reverted to direct Government control with management passing into the control of the Department of Tourist and Health Resorts. On 7th January 1903 by Order in Council the Government resumed control vesting the reserve in the Minister in Charge of Tourist and Health Resorts under the provisions of the Public Domains Act of 1881.

The science of baleanology and the importance of the hot pools for their curative purposes filled an important role at the Te Aroha spa. Reporting for the year 1905 to 1906 Dr Kenny notes the great increase in public rather than private bathing. He attributes this switch to some very large public excursions from the goldfield townships, the large majority of who preferred a warm plunge rather than a private bath, "in other words they bathed for pleasure, rather than for the relief of ailments."

The Te Aroha spa continued to be as important for curative purposes as it was for recreation and enjoyment throughout the first half of the twentieth century. In 1906 massage rooms were fitted up and an operator installed, and in 1929 a new massage room was built onto the rear of the Cadman Bath House and updated X-ray equipment was installed. As late as 1950 a qualified physiotherapist was practising, providing massage and special treatments and provided 4,000 treatments in the year 1949-50.

Despite the fact that Rotorua, which was now linked into the North Island rail network, had eclipsed Te Aroha in terms of visitor numbers, the popularity of the Domain grew throughout the first decade of the nineteenth century.

In January 1903 a new bowling green was opened that proved very popular and was considered one of the best in the country. The same year a grass tennis court and another croquet lawn were opened and Domain staff was increased from two bath attendants to four, and with the appointment of head gardener. In 1905 the cold swimming bath was repaired and reopened and a Bath House provided.

The Te Aroha Municipal Band provided regular open-air concerts during the season, with Japanese lanterns hanging from trees lighting the Domain. Facilities continued to be improved with the gardener's cottage built in 1906, electric light installed in 1906 and the Tea Kiosk opened in December 1908.

 

Te Aroha was an important sporting centre as well. Two new asphalt tennis courts were provided in 1908. Bowling and croquet tournaments were often held in the Domain with teams coming from the top half of the North Island.

The township complemented the Domain with a variety of licensed hotels and private hotels. At the peak of its popularity there were five hotels and eight boarding houses.

The Domain was a popular picnic spot and school parties regularly came on special excursion trains. There were walks along the river to the waterfall behind the Domain, to the glow-worms in an old mining tunnel behind the Domain, to Bald-Spur and to a defensive pa south of the waterfall. Te Aroha was an especially popular destination for day-trippers on public holidays. On New Years Day 1912, 7,000 visitors arrived in Te Aroha for the day. Many of these arrived on special excursion trains from Auckland, which took five hours each way.

The decline in popularity of the Domain was gradual. With the construction of a new railway, Rotorua soon took over from Te Aroha as the pre-eminent Spa. Advances in medical science saw a discrediting and loss of faith in ‘scientific baleanology’, and changing fashions saw the concept of the fashionable spa fall out of favour. People still continued to use the baths, with more emphasis on casual enjoyment than the more formal ‘taking of the waters’. The Tea Kiosk closed in 1923 because it was losing money. In 1928 a new tepid swimming bath was opened when mixed bathing was introduced, but the No. 4 and No. 6 Bath Houses were closed around the same time.

Troops stationed near Te Aroha during the Second World War saw a brief revival in the fortunes of the pools, but the long-term decline continued.

In 1953 the Department of Tourist and Health Resorts offered the Domain to the Te Aroha Borough Council as a gift together with a subsidy for a period of years, but the offer was declined. The decline in use of the Domain facilities provided opportunity for new functions to operate. A skating rink was built over the old asphalt tennis court in 1956. The Museum took over the Cadman Bath House after the Bowling Club occupied it. The gardener's cottage, now a cafe, was then used by the Department of Conservation (DOC) as their office and Information Centre.