Hastings' Dictionary of the New Testament 
Bithynia (Βιθυνία) was a fertile and highly civilized country in the N.W. of Asia Minor, bounded en the W. by the Propontis and the Bosporus, on the N. by the Euxine, on the S. by the range of Mysian Olympus, and on the E. by a doubtful line, some distance to the right of the river Sangarios (Strabo, xii. iv. 1; Pliny, v. 43). One of the kings of Bithynia changed the history of Asia Minor by inviting the marauding Galatians to cross the Bosporus (278 b.c.). Nicomedes iii., the last king, made the Romans his heirs (73 b.c.), and after the expulsion of Mithridates of Pontus (64 b.c.), Pompey formed the dual province of Bithynia et Pontus , which was governed by a proconsul, residing at Nicomedeia. On the division of the provinces by Augustus in 27 b.c. it remained senatorial.
The presence of Jews in Bithynia is indicated by Philo ( Leg. ad Gaium , 36). In his second missionary journey, St. Paul, always drawn to the great centres of Graeco-Roman civilization, attempted with Silas to enter Bithynia (ἐπείραζον εἰς τὴν Βιθυνίαν πορευθῆναι), intending probably to evangelize Nicaea and Nicomedeia, but the Spirit of Jesus, who was leading them on westward, did not permit them ( Acts 16:7). The province which so nearly became an apostolic mission-field had not, however, to wait long for the gospel. 1 Peter 1:1 affords evidence of the early introduction and rapid progress of Christianity in the province of Bithynia. Details, however, are wanting.
‘For Bithynia, like Cappadocia, we have no primitive Christian record: but it could hardly remain long unaffected by the neighbourhood at Christian communities to the South-West, the South, and probably the East; even if no friend or disciple took up before long the purpose which St. Paul had been constrained to abandon, when a Divine intimation drew him onward into Europe’ (F. J. A. Hort, First Ep. of St. Peter: I. 1-II; 17 , 1898, p. 17).
In a.d. 112 the younger Pliny was sent to govern the province of Bithynia, which had become disorganized under senatorial administration. His correspondence with Trajan bears striking testimony to the expansion of the Christian religion, which seemed to him a superstitio prava immodica ( Epp . x. 96, 97). Not only in the cities but in the rural villages the temples were almost deserted and the sacrificial ritual interrupted. While the letters describe a state of things which was true of the province as a whole, there are some indications that Amisos in the Far East was the first city on the Black Sea to which Christianity spread (Ramsay, The Church in the Roman Empire , 1893, p. 224f.).
Literature.-W. Smith, DGRG [Note: GRG Dict. of Greek and Roman Geography.]i.  404; Carl Ritter, Kleinasien , i.  650ff.; E. G. Hardy, Plinii Epistulae ad Trajanum , 1889; W. M. Ramsay. Hist. Geog. of Asia Minor , 1890; Conybeare-Howson, Life and Epistles of St. Paul , new ed., 1877.
Fausset's Bible Dictionary 
Paul and Silas from Mysia "assayed to go into Bithynia, but the Spirit of Jesus (so the Sin., Vaticanus, and Alexandrinus, the oldest manuscripts, read) suffered them not" ( Acts 16:7). But afterward the gospel reached Bithynia; and Bithynians, both Jews and Gentiles. Peter, became Christians; for Peter ( 1 Peter 1:1) addresses them along with those of "Pontus, Galatia, Cappadocia, and Asia." (See Peter .) Delay is not denial of believing prayer; God's time, God's place, and God's way are the best. Bithynia is the nearest point to Europe; bounded by Paphlagonia on the E., by the Euxine on the N., by the Propontis on the W, by Mysia, Phrygia, and Galatia on the S. Bithynia was originally bequeathed to Rome by Nicomedes III, 74 B.C., the last of the kings, one of whom invited the Gauls; whence the central province was called Gallo-Graecia or Galatia.
On the death of Mithridates king of Pontus, 63 B.C., the W. of Pontus including Paphlagonia was joined to Bithynia. The Roman province is sometimes called "Pontus and Bithynia." In Acts 2:9 Pontus alone is mentioned, in 1 Peter 1:1 both are mentioned. It is hilly, well wooded, and productive. The river Rhyndacus, and the snowy range of mount Olympus of Mysia, are marked features on the W. At Nicaea in it met the famous council early in the 4th century. In the 2nd century Pliny the Younger, its governor, wrote the letter still extant to the emperor Trajan: "in the case of those Christians who were brought before me I adopted this method. I asked them, Were they Christians? On their confessing it, I asked them a second and third time, threatening punishment. When they persevered I ordered them to be led off for execution.
For I did not doubt that inflexible obstinacy ought to he punished. Nothing can compel those who are real Christians to call on the gods, and supplicate thy image with frankincense and wine, and to curse Christ. Their error is this; they are wont to meet on a stated day before dawn and to repeat in turns among themselves a hymn to Christ as God; and to bind themselves by oath not to commit any wickedness, such as theft, robbery, or adultery, nor to break their word. When this is over, their custom is to depart and to meet again to take food, but ordinary and innocuous. Many of every age and rank, also of both sexes, are in question. For the contagion of that superstition has spread not only through cities, but even villages and the country. At least it is certain that our temples now are almost deserted, and the customary sacred rites for long omitted, and a purchaser of victims is very rarely found."
American Tract Society Bible Dictionary 
1 Peter 1:1 , a providence in the northern part of Asia Minor, on the shore of the Black sea, having Paphlagonia on the east, Phrygia and Galatia on the south, and Mysia on the southwest. It was directly opposite to Constantinople. It is famous as being one of the provinces to which the apostle Peter addressed his first epistle; also as having been under the government of Pliny, who, in a letter to the emperor Trajan, makes honorable mention of the number, character, and customs of the persecuted Christians there, about A. D. 106; also for the holding of the most celebrated council of the Christian church in the city of Nice, its metropolis, about A. D. 325. It may be, with some justice, considered as a province taught by Peter; and we read that when Paul attempted to go into Bithynia, the Spirit suffered him not, Acts 16:7 .
Hastings' Dictionary of the Bible 
BITHYNIA . A district in the N.W. of Asia Minor, which had been a Roman province since b.c. 74. For administrative purposes it was generally united with the province of Pontus, which bounds it on the E., under one governor. The province was senatorial till about a.d. 165, and governed by a proconsul. The younger Pliny governed it from a.d. 111 113 by a special commission from the emperor Trajan. Paul and Silas were prevented by the Spirit from preaching in Bithynia ( Acts 16:7 ), and the beginnings of Christianity there are unknown. It is probable that it came by the Black Sea. That there were churches there after St. Paul’s time is certain from the address of the First Epistle of Peter, which was probably written a.d. 75 80.
Watson's Biblical & Theological Dictionary 
a country of Asia Minor, stretching along the shore of the Pontus Euxinus, or Black Sea, from Mysia to Paphlagonia; having Phrygia and Galatia on the south. In it are the two cities of Nicaea, or Nice, and Chalcedon: both celebrated in ecclesiastical history, on account of the general councils held in them, and called after their names. The former city is at present called Is-Nick, and the latter Kadi-Keni. Within this country, also, are the celebrated mountains of Olympus. St. Peter addressed his first Epistle to the Hebrew Christians who were scattered through this and the neighbouring countries.
Morrish Bible Dictionary 
A large district in the north of Asia Minor, bordering on the Black Sea. Paul and Timotheus attempted to go into Bithynia, but the Spirit suffered them not. Acts 16:7 . Peter addressed his first Epistle to those of the dispersion of Bithynia, etc. 1 Peter 1:1 . It was then a Roman province: it is now called Kastamuni, a part of Turkey in Asia.
Smith's Bible Dictionary 
Bithyn'ia. A Roman province of Asia Minor. Mentioned only in Acts 16:7, and in 1 Peter 1:1. The chief town of Bithynia was Nicaea, celebrated for the general Council of the Church, held there in A.D. 325, against the Arian heresy.
People's Dictionary of the Bible 
Bithynia ( Bî'Thĭn'I-Ah ). A rich Roman province of Asia Minor, on the Black Sea; named only twice in scripture. Acts 16:7; 1 Peter 1:1.
Holman Bible Dictionary 
Acts 16:7 1 Peter 1:1
Easton's Bible Dictionary 
1 Peter 1:1 Acts 16:7
Cyclopedia of Biblical, Theological and Ecclesiastical Literature 
International Standard Bible Encyclopedia 
bi - thin´i - a ( Βιθυνία , Bithunı́a ): A coast province in northwestern Asia Minor on the Propontis and the Euxine. Its narrowest compass included the districts on both sides of the Sangarius, its one large river, but in prosperous times its boundaries reached from the Rhyndacus on the west to and beyond the Parthenius on the east. The Mysian Olympus rose in grandeur to a height of 6,400 ft. in the southwest, and in general the face of Nature was wrinkled with rugged mountains and seamed with fertile valleys sloping toward the Black Sea.
Hittites may have occupied Bithynia in the remote past, for Priam of Troy found some of his stoutest enemies among the Amazons on the upper Sangarius in Phrygia, and these may have been Hittite, and may easily have settled along the river to its mouth. The earliest discernible Bithynians, however, were Thracian immigrants from the European side of the Reliespont. The country was overcome by Croesus, and passed with Lydia under Persian control, 546 bc. After Alexander the Great, Bithynia became independent, and Nicomedes I, Prusias I and II, and Nicomedes Ii and III, ruled from 278 to 74 bc. The last king, weary of the incessant strife among the peoples of Asia Minor, especially as provoked by the aggressive Mithridates, bequeathed his country to Rome. Nicomedia and Prusa, or Brousa, were founded by kings whose names they bear; the other chief cities, Nicea and Chalcedon, had been built by Greek enterprise earlier. There were highways leading from Nicomedia and Nicea to Dorylaeum and to Angora (see Ramsay, Historical Geography of Asia Minor , and The Church in the Roman Empire before ad 170 ). Under Rome the Black Sea littoral as far as Amisus was more or less closely joined with Bithynia in administration.
Paul and Silas essayed to go into Bithynia, but the Spirit suffered them not ( Acts 16:7 ). Other evangelists, however, must have labored there early and with marked success. Bithynia is one of the provinces addressed in 1 Peter 1:1 .
Internal difficulties and disorders led to the sending of Pliny, the lawyer and literary man, as governor, 111 to 113 ad. He found Christians under his jurisdiction in such numbers that the heathen temples were almost deserted, and the trade in sacrificial animals languished. A memorable correspondence followed between the Roman governor and the emperor Trajan, in which the moral character of the Christians was completely vindicated, and the repressive measures required of officials were interpreted with leniency (see E. G. Hardy, Pliny's Correspondence with Trajan , and Christianity and the Roman Government ). Under this Roman policy Christianity was confirmed in strength and in public position. Subsequently the first Ecumenical Council of the church was held in Nicea, and two later councils convened in Chalcedon, a suburb of what is now Constantinople. The emperor Diocletian had fixed his residence and the seat of government for the eastern Roman Empire in Nicomedia.
Bithynia was for a thousand years part of the Byzantine Empire, and shared the fortunes and misfortunes of that state. On the advent of the Turks its territory was quickly overrun, and Orchan, sultan in 1326, selected Brousa as his capital, since which time this has been one .of the chief Ottoman cities.
Kitto's Popular Cyclopedia of Biblial Literature 
Bithyn′ia, a province of Asia Minor, on the Euxine Sea and the Propontis; bounded on the west by Mysia, on the south and east by Phrygia and Galatia, and on the east by Paphlagonia. The Bithynians were a rude and uncivilized people, Thracians who had colonized this part of Asia, and occupied no towns, but lived in villages. That Christian congregations were formed at an early period in Bithynia, is evident from the Apostle Peter having addressed the first of his Epistles to them ( 1 Peter 1:1). The Apostle Paul was at one time inclined to go into Bithynia with his assistants Silas and Timothy, 'but the Spirit suffered him not' ( Acts 16:7).
The Nuttall Encyclopedia 
A country in the NW. of Asia Minor, anciently so called; the people of it were of Thracian origin.
- Bithynia from Hastings' Dictionary of the New Testament
- Bithynia from Fausset's Bible Dictionary
- Bithynia from American Tract Society Bible Dictionary
- Bithynia from Hastings' Dictionary of the Bible
- Bithynia from Watson's Biblical & Theological Dictionary
- Bithynia from Morrish Bible Dictionary
- Bithynia from Smith's Bible Dictionary
- Bithynia from People's Dictionary of the Bible
- Bithynia from Holman Bible Dictionary
- Bithynia from Easton's Bible Dictionary
- Bithynia from Cyclopedia of Biblical, Theological and Ecclesiastical Literature
- Bithynia from International Standard Bible Encyclopedia
- Bithynia from Kitto's Popular Cyclopedia of Biblial Literature
- Bithynia from The Nuttall Encyclopedia