The first USS Gettysburg was a steamer in the United States Navy. The ship was built in Glasgow, Scotland, in 1858, named RMS Douglas, and operated by the Isle of Man Steam Packet Company in the United Kingdom between Liverpool, England, and Douglas on the Isle of Man until November 1862. She was then sold to Cunard, Wilson & Company on behalf of the Confederate agents Fraser, Trenholm & Company for use by the Confederate States of America during the American Civil War. Renamed Margaret and Jessie, she operated as a blockade runner until her capture by the Union on 5 November 1863. The ship then was commissioned into the Union Navy on 2 May 1864 as USS Gettysburg.

During her U.S. Navy service, Gettysburg operated with the North Atlantic Blockading Squadron, was involved in both the first and second attacks on Fort Fisher, helped lay telegraph cables between Key West, Florida, and Havana, Cuba, and undertook navigational surveys of the Caribbean Sea, the Atlantic Ocean, and the Mediterranean Sea. Gettysburg was decommissioned on 6 May 1879 and sold two days later.

Isle of Man Steam Packet Company, 1858–1862 Construction Due to a steady increase in passenger traffic between the Isle of Man and England, the Isle of Man Steam Packet Company decided in 1858 to order a larger, faster ship for its packet fleet. The ship, PS Douglas, No. 20683, the first ship in the company's history to be so named and the ninth ship the company ordered, was an iron-hulled paddle steamer. She was built by Robert Napier and Sons in Glasgow, Scotland, in 1858. Robert Napier and Sons also supplied her steam engine and boilers. Her purchase cost was £17,500, plus an allowance from John Napier and Sons of £5,000 for the paddle steamer of 1842.

Douglas was launched at 13:30 hours on Wednesday, 28 April 1858, the christening of the ship being performed by the wife of John Napier. Also in attendance on behalf of the Isle of Man Steam Packet Company was Captain Edward Quayle, the commodore of the company.Mona's Herald, Wednesday, 5 May 1858; Page: 3

Douglas′s launch had been delayed for a short period as the berth where her fitting-out was to take place was occupied by another vessel. Following her launch she was towed to Launcefield Dock in order to receive her engines.Manx Sun, Saturday, 1 May 1858; Page: 12

During sea trials, Douglas achieved and was declared the fastest channel steamer in existence at the time. Her service speed was .

Appearance and furnishings Designed to carry a mixture of passengers and cargo, Douglas was the first steam packet with a straight stern, no fiddle bow, and no figurehead. Her gross tonnage was , her length , her beam , and her depth . Certified by the Board of Trade to carry between 800 and 900 passengers, she was longer and faster than her forerunners.

Douglas was considered an elegant ship. She had a raised quarterdeck, below which was situated a spacious and beautifully fitted up saloon, ladies cabin, and sleeping cabins, with accommodation for 100 first class passengers. These cabins ran the full length of the quarterdeck and were lit by large, wide skylights, two large deck windows, and sixteen side windows. The chief saloon was well decorated with three large marble tables with mahogany tops, the seats for which had a movable back to allow the occupier to sit either facing toward or away from the table. On the wall at the aft end of the saloon were hung two pictures, one of Douglas Harbour and the other of Liverpool. The saloon could accommodate 70 people for dining at any given time.Mona's Herald, Wednesday, 7 July 1858; Page: 3

Steerage passengers were accommodated in the forward part of the ship, and as was the case with first class, a ladies lounge was provided. The crew's quarters were situated beyond this, in the immediate vicinity of the forecastle.

Douglas′s deck was described as clear and roomy, with a hurricane deck situated between the paddle boxes which was long and roofed over on all sides. She was fitted with a full complement of lifeboats, these being fitted with Clifford's patent lowering apparatus, which enabled the boats to be lowered safely whilst the vessel was under steam.

Mail, cargo, and machinery

Douglas′s designation as a Royal Mail Ship (RMS) indicated that she carried mail under contract with the Royal Mail. A specified area was allocated for the storage of letters, parcels, and specie (i.e., bullion, coins and other valuables). This was situated in the forecastle beneath the crew's quarters and was accessible only to a designated ship's officer.

Douglas′s cargo hold was below the main saloon and first class ladies cabin in one of the watertight compartments, giving Douglas space for a considerable quantity of regular cargo, ranging from furniture to foodstuffs.

Douglas′s cargo hold also contained two fresh water storage tanks, each capable of accommodating of water. Aft of the cargo hold were the fuel bunkers, furnaces, and steam engine.

Maiden voyage Douglas made her maiden voyage from Glasgow to Douglas, Isle of Man, on Saturday, 3 July 1858. Having made passage from the River Clyde in a time of 8 hours 30 minutes, her arrival off Onchan Head was heralded by cannon fire from the Conister Rock, Fort Anne, and the Castle Mona. As she entered Douglas Bay she stopped and embarked several directors of the Isle of Man Steam Packet Company before steaming across the bay several times among a large number of small boats which had put to sea for the occasion. A large crowd had gathered on the Red Pier in order to welcome her and after she had secured alongside many of these people were able to view the interior of the ship, with further public viewings made available over the following two days.

Douglas was claimed to be the fastest steamer then afloat. She attracted wide attention, and her speed made her a strong candidate for more advanced adventures and was acclaimed as "comme le premier" among cross-channel steamers.Manx Sun, Saturday, 4 April 1863; Page: 4

Service life Under the command of Captain Quayle, Douglas made her inaugural crossing from Douglas to Liverpool on Tuesday, 6 July 1858. She achieved over on the trip and immediately broke the record for the crossing time between Douglas and Liverpool, achieving a time of 4 hours 20 minutes.This broke the previous record of 4 hours 50 minutes set in September 1856 by .Manx Sun, Saturday, 24 July 1858; Page: 4 On her return run to the Isle of Man, Douglas would routinely record a passage time of 4 hours 40 minutes. Ancillary work consisted of charter sailings and day excursions, one of which was on 14 October 1859, when Douglas made an excursion to Holyhead, Wales, to see the ocean liner .Mona's Herald, Wednesday, 26 October 1859; Page: 7 On another occasion, she was chartered to Henderson's of Belfast, Ireland, for three weeks for the then-notable fee of £200 per week.

While in the Isle of Man Steam Packet Company's colours, the only events of interest – apart from the way she broke the record for the home run – were two mishaps that occurred during her voyages. One was her collision with the brig Dido, which cost the company £400 in damages. Another was an accident which befell a passenger on Monday, 16 April 1860, whilst she was making passage to Liverpool. The passenger, a sailor from the second rate ship-of-the-line who had been home on leave from the Royal Navy, scaled his way up the foremast head whilst in a state of alcohol intoxication and got onto the forestay. In his attempt to come back down he fell some to the deck. He subsequently was treated by a doctor who happened to be on board, and on arrival in Liverpool was transferred to the Northern Hospital.Mona's Herald, Wednesday, 18 April 1860; Page: 11

Confederate States of America, 1862–1863 Thanks to her high speed, Douglas was an ideal blockade runner for the Confederate States of America to use to avoid the Union blockade during the American Civil War. After only four years under Isle of Man Steam Packet Company ownership, Douglas was sold to Cunard, Wilson and Company — who were clandestinely acting as brokers for the Confederate agents Fraser, Trenholm and Company — for £24,000 in 1862. Douglas departed her home port of Douglas for the last time on Sunday, 16 November 1862,Manx Sun, Saturday, 22 November 1862; Page: 4 and proceeded to Liverpool.

Whilst in Liverpool Douglas was painted light grey and loaded with cargo. She departed for Nassau in the Bahamas under the command of Captain Corbett on Tuesday, 2 December 1862,Manx Sun, Saturday, 13 December 1862; Page: 4 and arrived at Nassau in late January 1863.Manx Sun, Saturday, 7 February 1863; Page: 4 By then she was under the ownership of the Charleston Import and Export Company. She successfully ran the blockade and reached Charleston, South Carolina, on 31 January 1863, bringing in much-needed supplies. She then departed for Nassau with a cargo of cotton. She subsequently was renamed Margaret and Jessie in honor of the daughters of her new owner, both of whom were on board her during her initial outbound blockade run from Charleston.Manx Sun, Saturday, 21 March 1863; Page: 12

Margaret and Jessie ran the blockade successfully on numerous other occasions. On 1 June 1863 off Nassau, however, Margaret and Jessie was fired upon and driven ashore by a United States Navy gunboat. Some records erroneously maintain that after she was driven ashore and had escaped to Nassau, she took no further part in the American Civil War, and that her engines could be seen rusting on the beach at Nassau as late as 1926. In reality, although damaged, she went back to blockade running a few days after her encounter with the gunboat.

On 5 November 1863, Margaret and Jessie′s blockade-running career came to an end when the United States Army transport Fulton and the U.S. Navy armed sidewheel paddle steamers and captured her off Wilmington, North Carolina, and took her as a prize.

U.S. Navy, 1864–1879 Acquisition, refit, and commissioning The U.S. Navy purchased Margaret and Jessie from the New York Prize Court for American Civil War service. She underwent a refit, emerging from it lengthened by to , armed with a 30-pounder Parrott rifle, two 12-pounder rifles, and four 24-pounder howitzers, and with a displacement of 950 tons. She was commissioned into U.S. Navy service as USS Gettysburg at the New York Navy Yard in Brooklyn, New York, on 2 May 1864 with Lieutenant Roswell Lamson commanding. When commissioned, she had a ship's company of 96.

American Civil War service North Atlantic Blockading Squadron A fast, strong steamer, Gettysburg was assigned to blockade duty with the North Atlantic Blockading Squadron. She departed New York City on 7 May 1864 and arrived at Beaufort, North Carolina, on 14 May 1864. From there she took station at the entrance to the Cape Fear River. For the next seven months, she was engaged in capturing Confederate blockade runners. She captured several ships. She occasionally performed other duties, such as on 8 October 1864, when she rescued six survivors from the schooner Home, which had capsized in a squall.

Battles of Fort Fisher Gettysburg took part in the First Battle of Fort Fisher on 24–25 December 1864. Gettysburg assisted with a devastating bombardment of Fort Fisher prior to amphibious landings by Union Army troops. During the actual landings, she stood in close to shore to furnish cover for the assault. Gettysburgs boats helped transport troops to the beaches.